U.S. patent number 11,206,164 [Application Number 17/158,758] was granted by the patent office on 2021-12-21 for short training sequence design method and apparatus.
This patent grant is currently assigned to Huawei Technologies Co., Ltd.. The grantee listed for this patent is Huawei Technologies Co., Ltd.. Invention is credited to Ming Gan, Dandan Liang, Xin Zuo.
United States Patent |
11,206,164 |
Zuo , et al. |
December 21, 2021 |
Short training sequence design method and apparatus
Abstract
The application provides a short training sequence design method
and apparatus. The method includes: determining a short training
sequence, where the short training sequence may be obtained based
on an existing sequence, and the short training sequence with
comparatively good performance may be obtained through simulation
calculation, for example, by adjusting a parameter; and sending a
short training field on a target channel, where the short training
field is obtained by performing inverse fast Fourier transformation
IFFT on the short training sequence, and a bandwidth of the target
channel is greater than 160 MHz.
Inventors: |
Zuo; Xin (Shenzhen,
CN), Gan; Ming (Shenzhen, CN), Liang;
Dandan (Shenzhen, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Huawei Technologies Co., Ltd. |
Shenzhen |
N/A |
CN |
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Assignee: |
Huawei Technologies Co., Ltd.
(Shenzhen, CN)
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Family
ID: |
1000006007681 |
Appl.
No.: |
17/158,758 |
Filed: |
January 26, 2021 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20210168005 A1 |
Jun 3, 2021 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/CN2019/096291 |
Jul 17, 2019 |
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Foreign Application Priority Data
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Jul 27, 2018 [CN] |
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201810846832.3 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L
27/2695 (20130101); H04L 27/2602 (20130101); H04L
27/2692 (20130101) |
Current International
Class: |
H04L
27/26 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101527664 |
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Sep 2009 |
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CN |
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105162745 |
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Dec 2015 |
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CN |
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107508780 |
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Dec 2017 |
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CN |
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108040028 |
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May 2018 |
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CN |
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2013152111 |
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Oct 2013 |
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WO |
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Other References
IEEE P802.11ax.TM./D3.0, Draft Standard for Information
technology--Telecommunications and information exchange between
systems Local and metropolitan area networks--Specific
requirements; Part 11: Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications; Amendment 6: Enhancements for
High Efficiency WLAN, Jun. 2018, 682 pages. cited by applicant
.
Noh, Y. et al., "Gamma phase rotation He PPDU", IEEE
802.11-16/0903r1, IEEE-SA Mentor, Piscataway, NJ, US, Jul. 25,
2016, 26 pages. cited by applicant .
Park, E. et al., "Overview of PHY Features for EHT", IEEE
802.11-18/1967r1, IEEE-SA Mentor, Piscataway, NJ, US, Jan. 14,
2019, 22 pages. cited by applicant.
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Primary Examiner: Tran; Khanh C
Attorney, Agent or Firm: Slater Matsil, LLP
Claims
What is claimed is:
1. A method, comprising: determining a short training sequence; and
sending a short training sequence on a target channel, wherein a
bandwidth of the target channel is 320 MHz; and wherein the short
training sequence satisfies the following: the short training
sequence has a periodicity of 0.8 .mu.s and is expressed by using
the following relation: S.sub.-2032:16:2032={c.sub.1.times.(M, 1,
-M), 0, c.sub.2.times.(-M, 1, -M), a.sub.1,c.sub.3.times.(M, 1,
-M), 0,c.sub.4.times.(-M, 1, -M), 0, c.sub.5.times.(M, 1, -M), 0,
c.sub.6.times.(-M, 1, .times.M), a.sub.2, c.sub.7.times.(M, 1, -M),
0, c.sub.8.times.(-M, 1, -M)}.times.(1+j)/ {square root over (2)};
or the short training sequence has a periodicity of 1.6 .mu.s and
is expressed by using the following relation:
S.sub.-2040:8:2040={c.sub.1.times.(M, -1, M, -1, -M-1, M), 0,
c.sub.2-(-M, 1, M, 1, -M, 1, -M), a.sub.1,c.sub.3.times.(M , -1, M,
-1, -M, -1, M), 0,c.sub.4.times.(-M, 1, M, 1, -M, 1, -M), 0,
c.sub.5.times.(M, -1, M, -1, -M, -1, M), 0, c.sub.6.times.(-M, 1,
M, 1, -M, 1, -M), a.sub.2, c.sub.7.times.(M, -1, M, -1, -M, -1, M),
0, c.sub.8.times.(-M, 1, M, 1, -M, 1, -M)}.times.(1+j)/ {square
root over (2)}; and wherein a value of a.sub.i is {-1, 0, 1}, i=1,
2, a value of c.sub.j is {-1, 1}, j=1, 2, 3, 4, 5, 6, 7, 8, and
M={-1,-1,-1,1,1,-1,1,1,1,-1,1,1,-1,1}.
2. The method according to claim 1, wherein a 320 MHz tone plan
uses four duplicated tone plans of 80 MHz, the 320 MHz bandwidth
has 4096 total tones, 12 guard tones are at a left edge of the 320
MHz bandwidth, and 11 guard tones are at a right edge of the 320
MHz bandwidth.
3. The method according to claim 1, wherein the 320 MHz bandwidth
has 23 direct-current tones in a middle of the 320 MHz
bandwidth.
4. An apparatus, comprising: a processor coupled to a
non-transitory memory configured to store program instructions for
execution by the processor, wherein when the program instructions
are executed, the communication apparatus is configured to:
determine a short training sequence; and send a short training
sequence on a target channel, wherein a bandwidth of the target
channel is 320 MHz; and wherein the short training sequence
satisfies the following: the short training sequence has
periodicity of 0.8 .mu.s and is expressed using the following
relation: S.sub.-2032:16:2032={c.sub.1.times.(M , 1, -M), 0,
c.sub.2.times.(-M, 1, -M), a.sub.1,c.sub.3.times.(M, 1, -M),
0,c.sub.4.times.(-M, 1, -M), 0, c.sub.5.times.(M , 1, -M), 0,
c.sub.6.times.(-M, 1, -M), a.sub.2, c.sub.7.times.(M , 1, -M), 0,
c.sub.8.times.(-M, 1, -M)}.times.(1+j)/ {square root over (2)}; or
the short training sequence has a periodicity of 1.6 .mu.s and is
expressed using the following relation:
S.sub.-2040:8:2040={c.sub.1.times.(M , -1, M, -1, -M, -1, M), 0,
c.sub.2.times.(-M, 1, M, 1, -M, 1, -M), a.sub.1,c.sub.3.times.(M ,
-1, M, -1, -M, -1, M), 0,c.sub.4.times.(-M, 1, M, 1, -M, 1, -M), 0,
c.sub.5.times.(M , -1, M, -1, -M, -1, M), 0, c.sub.6.times.(-M, 1,
M, 1, -M, 1, -M), a.sub.2, c.sub.7.times.(M, -1, M, -1, -M, -1, M),
0, c.sub.8.times.(-M, 1, M, 1, -M, 1, -M)}.times.(1+j)/ {square
root over (2)}; and wherein a value of a.sub.i is {-1, 0, 1}, i=1,
2, a value of c.sub.j is {-1, 1}, j=1, 2, 3, 4, 5, 6, 7, 8, and
M={-1,-1,-1,1,1,1,-1,1,1,1,-1,1,1,-1,1}.
5. The apparatus according to claim 4, wherein a 320 MHz tone plan
uses four duplicated tone plans of 80 MHz, the 320 MHz bandwidth
has 4096 total tones, 12 guard tones are at a left edge of the 320
MHz bandwidth, and 11 guard tones are at a right edge of the 320
MHz bandwidth.
6. The apparatus according to claim 4, wherein the 320 MHz
bandwidth has 23 direct-current tones in a middle of the 320 MHz
bandwidth.
7. A chip, comprising: one or more processing circuits, wherein the
one or more processing circuits are configured to: determine a
short training sequence; and send a short training sequence on a
target channel, wherein a bandwidth of the target channel is 320
MHz; wherein the short training sequence satisfies the following:
the short training sequence has a periodicity of 0.8 .mu.s, and is
expressed by using the following relation:
S.sub.-2032:16:2032={c.sub.1.times.(M, 1, -M), 0,
c.sub.2.times.(-M, 1, -M), a.sub.1,c.sub.3.times.(M, 1, -M),
0,c.sub.4.times.(-M, 1, -M), 0, c.sub.5.times.(M, 1, -M), 0,
c.sub.6.times.(-M, 1, -M), a.sub.2, c.sub.7.times.(M, 1, -M), 0,
c.sub.8.times.(-M, 1, -M)}.times.(1+j)/ {square root over (2)}; or
the short training sequence has a periodicity of 1.6 .mu.s, and is
expressed by using the following relation:
S.sub.-2040:8:2040={c.sub.1.times.(M , -1, M, -1, -M, -1, M),
a.sub.1, c.sub.3.times.(M, -1, M, -1, -M, -1, M),
0,c.sub.4.times.(-M, 1, M, 1, -M, 1, -M), 0, c.sub.5.times.(M, -1,
M, -1, -M, -1, M), 0, c.sub.6.times.(-M, 1, M, 1, -M, 1, -M),
a.sub.2, c.sub.7.times.(M, -1, M, -1, -M, -1, M) 0,
c.sub.8.times.(-M, 1, M, 1, -M, 1, -M)}.times.(1+j)/ {square root
over (2)}; and wherein a value of a.sub.i is {-1, 0, 1}, i=1, 2, a
value of c.sub.j is {-1, 1}, j=1, 2, 3, 4, 5, 6, 7, 8, and
M={-1,-1,-1,1,1,1,-1,1,1,1,-1,1,1,-1,1}.
8. The chip according to claim 7, wherein a 320 MHz tone plan uses
four duplicated tone plans of 80 MHz, the 320 MHz bandwidth has
4096 total tones, 12 guard tones are at a left edge of the 320 MHz
bandwidth, and 11 guard tones are at a right edge of the 320 MHz
bandwidth.
9. The chip according to claim 7, wherein the 320 MHz bandwidth has
23 direct-current tones in a middle of the 320 MHz bandwidth.
10. A non-transitory computer-readable storage medium, comprising
at least one segment of code, wherein when the at least one segment
of code is run on a computer, the computer is controlled to execute
the following: determine a short training sequence; and send a
short training sequence on a target channel, wherein a bandwidth of
the target channel is 320 MHz; and wherein the short training
sequence satisfies the following: the short training sequence has a
periodicity of 0.8 .mu.s, and is expressed by using the following
relation: S.sub.-2032:16:2032={c.sub.1.times.(M , 1, -M), 0,
c.sub.2.times.(.times.M, 1, -M), a.sub.1,c.sub.3.times.(M, 1, -M),
0,c.sub.4.times.(-M, 1, -M), 0, c.sub.5.times.(M , 1, -M), 0,
c.sub.6.times.(-M, 1, -M), a.sub.2, c.sub.7.times.(M , 1, -M), 0,
c.sub.8.times.(-M, 1, -M)}.times.(1+j)/ {square root over (2)}; or
the short training sequence has a periodicity of 1.6 .mu.s, and is
expressed by using the following relation:
S.sub.-2040:8:2040={c.sub.1.times.(M , -1, M, -1, -M, -1, M), 0,
c.sub.2.times.(-M, 1, M, 1, -M, 1, -M), a.sub.1,c.sub.3.times.(M ,
-1, M, -1, -M, -1, M), 0,c.sub.4.times.(-M, 1, M, 1, -M, 1, -M), 0,
c.sub.5.times.(M , -1, M, -1, -M, -1, M), 0, c.sub.6.times.(-M, 1,
M, 1, -M, 1, -M), a.sub.2, c.sub.7.times.(M, -1, M, -1, -M, -1, M),
0, c.sub.8.times.(-M, 1, M, 1, -M, 1, -M)}.times.(1+j)/ {square
root over (2)}; and wherein a value of a.sub.i is {-1, 0, 1}, i=1,
2, a value of c.sub.j is {-1, 1}, j=1, 2, 3, 4, 5, 6, 7, 8, and
M={-1,-1,-1,1,1,1,-1,1,1,1,-1,1,1,-1,1}.
11. The non-transitory computer-readable storage medium according
to claim 10, wherein a 320 MHz tone plans uses four duplicated tone
plan of 80 MHz, the 320 MHz bandwidth has 4096 total tones, 12
guard tones are at a left edge of the 320 MHz bandwidth, and 11
guard tones are at a right edge of the 320 MHz bandwidths.
12. The non-transitory computer-readable storage medium according
to claim 10, wherein the 320 MHz bandwidth has 23 direct-current
tones in a middle of the 320 MHz bandwidth.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of International Application No.
PCT/CN2019/096291, filed on Jul. 17, 2019, which claims priority to
Chinese Patent Application No. 201810846832.3, filed on Jul. 27,
2018. The disclosures of the aforementioned applications are hereby
incorporated by reference in their entireties.
TECHNICAL FIELD
This application relates to the communications field, and more
specifically, to a short training sequence design method and
apparatus.
BACKGROUND
During evolution from 802.11a to 802.11g, 802.11n, 802.11ac, and
802.11ax, available frequency bands include 2.4 gigahertz (GHz) and
.sub.5 GHz. As a quantity of open frequency bands increases, a
maximum channel bandwidth supported by 802.11 is extended from 20
megahertz (MHz) to 40MHz and then to 160 MHz. In 2017, the US
Federal Communications Commission (FCC) opened a new free 6-GHz
frequency band (5925-7125 MHz), and workers of the 802.11ax
standard extended an operating range of 802.11ax devices from 2.4
GHz and 5 GHz to 2.4 GHz, 5 GHz, and 6 GHz in the 802.11ax project
authorization requests (PAR). Because an available bandwidth of the
newly opened 6-GHz frequency band is higher, it can be predicted
that a channel bandwidth greater than 160 MHz is to be supported in
evolution of a next-generation standard after 802.11ax.
In this case, how to design a short training field (STF) is a
concern for a higher channel bandwidth.
SUMMARY
This application provides a short training sequence design method
and apparatus, so that a short training sequence can be designed
for a higher channel bandwidth, and backward compatibility can be
implemented.
According to a first aspect, a short training field sending method
is provided. The method includes: determining a short training
sequence; and sending a short training field on a target channel,
where the short training field is obtained by performing inverse
fast Fourier transformation IFFT on the short training sequence,
and a bandwidth of the target channel is greater than 160 MHz.
Based on the foregoing technical solution, a short training
sequence corresponding to a higher channel bandwidth is determined,
so that a receive end can perform automatic gain control on data
transmitted on the higher channel bandwidth. The short training
sequence may be obtained based on a short training sequence for an
existing channel bandwidth, and a short training sequence with
comparatively good performance may be obtained through simulation
calculation, for example, by adjusting a parameter. Then inverse
fast Fourier transformation is performed on the short training
sequence to obtain a short training field. According to this
embodiment of this application, a higher channel bandwidth can be
achieved in practice, and backward compatibility is implemented. In
addition, exhaustive simulation is performed on parameters to
verify that the short training sequence provided in this embodiment
of this application has a comparatively small peak-to-average power
ratio PAPR and comparatively good performance, thereby improving an
estimation effect for an automatic gain control circuit at a
receive end, and reducing a receive bit error rate.
With reference to the first aspect, in some implementations of the
first aspect, the short training sequence is obtained through
transformation based on an M-sequence, or the short training
sequence is obtained through transformation based on a high
efficiency frequency-domain sequence HES corresponding to a
bandwidth of a reference channel, where the bandwidth of the
reference channel is less than or equal to 160 MHz.
Based on the foregoing technical solution, the short training
sequence corresponding to the higher channel bandwidth may be
directly obtained based on the M-sequence. For example, it can be
learned from the 802.11ax standard that a high efficiency-short
training sequence HE-STF is constructed by performing multiplexing,
phase rotation, and combination based on the M-sequence. The
M-sequence is defined as M={-1, -1, -1, 1, 1, 1, 1, -1, 1, 1, 1,
-1, 1, 1, -1,} in the 802.11ax standard. Alternatively, the short
training sequence corresponding to the higher channel bandwidth may
be obtained based on a high efficiency frequency-domain sequence
HES corresponding to an existing channel, for example, an HES
corresponding to 80 MHz or 160 MHz, so as to be compatible with an
existing short training sequence. For the HES, the 802.11ax
standard defines a frequency-domain value HES.sub.a:b:c of the
HE-STF, where a indicates a subscript of a starting tone, c
indicates a subscript of an ending tone, b indicates a spacing, and
a:b:c indicates starting with a tone a and ending with a tone c,
with a spacing of b tones in between. On other tones, an HES value
is 0.
With reference to the first aspect, in some implementations of the
first aspect, the bandwidth of the target channel is 240 MHz; and
when a periodicity included in the short training field is 0.8
.mu.s, the short training sequence is expressed as follows:
{L1, 1, -R1, 1, -L1. 0, R1, 0, -L1, 0, -R1}(1+j)/ {square root over
(2)}; or
{-L1, -1, R1, -1, L1, 0, -R 1, 0, L1, 0, R1}(1+j)/ {square root
over (2)}; or
{L1, 1, -R1, -1, -L1, 0, -R1, 1, L1, 1, R1}(1+j)/ {square root over
(2)}; or
{-L1, -1, R1, 1, L1, 0, R1, -1, -L1, -1, -R1}(1+j)/ {square root
over (2)}; or
{L1, 1, -R1, 1, -L1, 0, R1, 1, -L1, 0, -R1}(1+j)/ {square root over
(2)}; or
{-L1, -1, R1, -1, L1, 0, -R1, -1, L1, 0R1}(1+j)/ {square root over
(2)}; or
{L1, 0-R1, 0, -L1, 0, R1, -1-L1, 0-R1}(1+j)/ {square root over
(2)}; or
{-L1, 0, R1, 0, L1, 0-R1, 1, L1, 0, R1}(1+j)/ {square root over
(2)}; or
{L1, 1, -R1, 0, -L1, 0, R1, -1, -L1, 0, -R1}(1+j)/ {square root
over (2)}; or
{-L1, -1, R1, 0, L 1, 0, -R1, 1, L1, 0, R1}(1+j)/ {square root over
(2)}; where
L1 is expressed as {M, 1, -M}, R1 is expressed as {-M, 1, -M}, -L1
is expressed as {-M, -1, M}, and -R1 is expressed as {M, -1,
M}.
In the foregoing technical solution, the 240-MHz bandwidth has 3072
tones in total. When the periodicity included in the short training
field is 0.8 .mu.s, the short training sequence may be expressed as
S.sub.-1520:16:1520, where -1520 indicates a subscript of a
starting tone, 1520 indicates a subscript of an ending tone, 16
indicates a spacing, and -1520:16:1520 indicates starting with a
tone whose subscript is -1520 and ending with a tone whose
subscript is 1520, with a spacing of 16 tones in between. On other
tones, a frequency-domain sequence value is 0. Therefore, the
values given by the foregoing short training sequence each
correspond to a frequency-domain sequence value that starts with a
tone whose subscript is -1520 and ends with a tone whose subscript
is 1520, with a spacing of 16 tones in between. L1 and R1 are
sequences related to a short training sequence corresponding to an
80-MHz short training field with a periodicity of 0.8 .mu.s.
Therefore, the 240-MHz short training sequence can be compatible
with the 80-MHz short training sequence. In addition, the 240-MHz
short training sequence can support automatic gain control on a
high-bandwidth (the bandwidth is greater than 160 MHz) channel. In
addition, it is verified through simulation that these short
training sequences have comparatively small peak-to-average power
ratios, and therefore can support automatic gain control on a
high-bandwidth channel and can improve an estimation effect for an
automatic gain control circuit at a receive end, thereby reducing a
receive bit error rate.
With reference to the first aspect, in some implementations of the
first aspect, the bandwidth of the target channel is 240 MHz; and
when the periodicity included in the short training field is 1.6
.mu.s, the short training sequence is expressed follows:
{L2, -1, -R2, -1, L2, 0, R2, 1-L2, 1, -R2}(1+j)/ {square root over
(2)}; or
{-L2, 1, R2, 1, -L2, 0-R2, -1, L2, -1, R2}(1+j)/ {square root over
(2)}; or
{L2, 0-R2, -1, L2, 0, R2, 1-L2, 1, -R2}(1+j)/ {square root over
(2)}; or
{-L2, 0, R2, 1, -L2, 0-R2, -1L2, -1, R2}(1+j)/ {square root over
(2)}; or
{L2, -1, -R2, -1, L2, 0, R2, 1, -L2, 0-R2}(1+j)/ {square root over
(2)}; or
{-L2, 1, R2, 1, L2, 0R2, 0, -L2, 1, -R2}(1+j)/ {square root over
(2)}; or
{L2, -1, -R2, -1, L2, 0, R2, 0-L2, 1, -R2}(1+j)/ {square root over
(2)}; or
{-L2, 1, R2, 1-L2, 0, -R2, 0, L2, -1, R2}(1+j)/ {square root over
(2)}; or
{L2, -1, -R2, 0, L2, 0, R2, 1, -L2, 1, -R2}(1+j)/ {square root over
(2)}; or
{-L2, 1, R2, 0, -L2, 0, -R2, -1, L2, -1, R2}(1+j)/ {square root
over (2)}; where
L2 is expressed as {M, -1, M, -1, -M, -1, M}, R2 is expressed as
{-M, 1, M, 1, -M, 1, -M}, -L2 is expressed as {-M, 1, -M, 1, -M},
and -R2 is expressed as {M, -1, -M, -1, M, -1, M}.
In the foregoing technical solution, the 240-MHz bandwidth has 3072
tones in total. When the periodicity included in the short training
field is 1.6 .mu.s, the short training sequence may be expressed as
S.sub.-1528:8:1528, where -1528 indicates a subscript of a starting
tone, 1528 indicates a subscript of an ending tone, 8 indicates a
spacing, and -1528:8:1528 indicates starting with a tone whose
subscript is -1528 and ending with a tone whose subscript is 1528,
with a spacing of 8 tones in between. On other tones, a
frequency-domain sequence value is 0. Therefore, the values given
by the foregoing short training sequence each correspond to a
frequency-domain sequence value that starts with a tone whose
subscript is -1528 and ends with a tone whose subscript is 1528,
with a spacing of 8 tones in between. L2 and R2 are sequences
related to an 80-MHz and 1.6-.mu.s short training sequence.
Therefore, the 240-MHz short training sequence can be compatible
with the 80-MHz short training sequence. In addition, the 240-MHz
short training sequence can support automatic gain control on a
high-bandwidth (the bandwidth is greater than 160 MHz) channel. In
addition, it is verified through simulation that these short
training sequences have comparatively small peak-to-average power
ratios, and therefore can support automatic gain control on a
high-bandwidth channel and can improve an estimation effect for an
automatic gain control circuit at a receive end, thereby reducing a
receive bit error rate.
With reference to the first aspect, in some implementations of the
first aspect, the bandwidth of the target channel is 320 MHz; and
when a periodicity included in the short training field is 0.8
.mu.s, the short training sequence is expressed as follows:
{L1, 0, -R1, 0, L1, 0, R1, 0, L1, 0, -R1, -1, -L1, 0-R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 0,-L1, 0-R1, 0-L1, 0R1, 1L1, 0, R1}(1+j)/ {square root
over (2)}; or
{L1, 0-R1, -1, L1, 0, -R1, 0, L1, 0-R1, -1, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 1, -L1, 0, -R1, 0-L1, 0-R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 0, -L1, 0, R1, 0, -L1, 0, -R1, -1, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 0, L1, 0, -R1, 0, L1, 0, R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 0, L1, 0, -R1, 0, -L1, 0, -R1, 0, L1, 0, R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 0, -L1, 0, R1, 0, L1, 0, R1, 0, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 1, L1, 0, -R1, 0, -L1, 0, -R1, -1, -L1, 0R1}(1+j)/
{square root over (2)}; or
{-L1, 0R1, -1, -L1, 0R1, 0L1, 0, R1, 1, -L1, 0, -R1}(1+j)/ {square
root over (2)}; where
L1 is expressed as {M, 1, -M}, R1 is expressed as {-M, 1, -M}, L1
is expressed as {-M, -1, M}, and -R1 is expressed as {M, -1,
M}.
In the foregoing technical solution, the 320-MHz bandwidth has 4096
tones in total. When the periodicity included in the short training
field is 0.8 .mu.s, the short training sequence may be expressed as
S.sub.-2032:16:2032, where -2032 indicates a subscript of a
starting tone, 2032 indicates a subscript of an ending tone, 16
indicates a spacing, and -2032:16:2032 indicates starting with a
tone whose subscript is -2032 and ending with a tone whose
subscript is 2032, with a spacing of 16 tones in between. On other
tones, a frequency-domain sequence value is 0. Therefore, the
values given by the foregoing short training sequence each
correspond to a frequency-domain sequence value that starts with a
tone whose subscript is -2032 and ends with a tone whose subscript
is 2032, with a spacing of 16 tones in between. L1 and R1 are
sequences related to a short training sequence corresponding to
80MHz and the periodicity of 0.8 .mu.s. Therefore, the 320-MHz
short training sequence can be compatible with the 80-MHz short
training sequence. In addition, the 320-MHz short training sequence
can support automatic gain control on a high-bandwidth (the
bandwidth is greater than 160 MHz) channel. In addition, it is
verified through simulation that these short training sequences
have comparatively small peak-to-average power ratios, and
therefore can support automatic gain control on a high-bandwidth
channel and can improve an estimation effect for an automatic gain
control circuit at a receive end, thereby reducing a receive bit
error rate.
With reference to the first aspect, in some implementations of the
first aspect, the bandwidth of the target channel is 320 MHz; and
when a periodicity included in the short training field is 0. 8
.mu.s, the short training sequence is expressed as follows:
{L3, 0,R3, 0, -L3, -1, R3}(1+j)/ {square root over (2)}; or
{-L3, 0, -R3, 0, L3, 1, -R3}(1+j)/ {square root over (2)}; or
{L3, 0, R3, 0, -L3, 0, R3}(1+j)/ {square root over (2)}; or
{-L3, 0, -R3, 0, L3, 0, -R3}(1+j)/ {square root over (2)}; or
{L3. 1-R3, 0, -L3, 1, -R3}(1+j)/ {square root over (2)}; or
{-L3, -1, R3, 0, L3, -1, R3}(1+j)/ {square root over (2)}; or
{L3, 1, -R3, 0, -L3, 0-R3}(1+j)/ {square root over (2)}; or
{-L3, 1, R3, 0, L3, 0, -R3}(1+j)/ {square root over (2)}; or
{L3, -1, -R3, 0, L3, 1, -R3}(1+j)/ {square root over (2)}; or
{-L3, -1, -R3, 0, L3, 1, -R3}(1+j)/ {square root over (2)};
where
L3 is expressed as {M, 1,-M, 0, -M, 1, -M}, R3 is expressed as {-M,
-1, M, 0, -M, 1, -M}, -L3 is expressed as {-M, -1, M, 0, M, -1, M},
and -R3 is expressed as {M, 1, -M, 0, M, -1, M}.
In the foregoing technical solution, the 320-MHz bandwidth has 4096
tones in total. When the periodicity included in the short training
field is 0.8 .mu.s, the short training sequence may be expressed as
S.sub.-2032:16:2032, where -2032 indicates a subscript of a
starting tone, 2032 indicates a subscript of an ending tone, 16
indicates a spacing, and -2032:16:2032 indicates starting with a
tone whose subscript is -2032 and ending with a tone whose
subscript is 2032, with a spacing of 16 tones in between. On other
tones, a frequency-domain sequence value is 0. Therefore, the
values given by the foregoing short training sequence each
correspond to a frequency-domain sequence value that starts with a
tone whose subscript is -2032 and ends with a tone whose subscript
is 2032, with a spacing of 16 tones in between. L3 and R3 are
sequences related to a short training sequence corresponding to 160
MHz and the periodicity of 0.8 .mu.s. Therefore, the 320-MHz short
training sequence can be compatible with the 160-MHz short training
sequence. In addition, the 320-MHz short training sequence can
support automatic gain control on a high-bandwidth (the bandwidth
is greater than 160 MHz) channel. In addition, it is verified
through simulation that these short training sequences have
comparatively small peak-to-average power ratios, and therefore can
support automatic gain control on a high-bandwidth channel and can
improve an estimation effect for an automatic gain control circuit
at a receive end, thereby reducing a receive bit error rate.
With reference to the first aspect, in some implementations of the
first aspect, the bandwidth of the target channel is 320 MHz; and
when the periodicity included in the short training field is 1.6
.mu.s, the short training sequence is expressed as follows:
{L2, 0, -R2, 1, L2, 0, -R2, 0, L2, 0, R2, -1, -L2, 0, --R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 1, -L2, 0, R2, 0, -L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 0, L2, 0, -R2, 0, L2, 0, R2,-1, -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 0, -L2, 0, R2, 0, L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, -1, L2, 0, -R2, 0, L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 1, -L2, 0, R2, 0, -L2, 0, -R2, 0, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 1, L2, 0, -R2, 0, L2, 0, R2, -1, L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, -1, -L2, 0, R2, 0, -L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 0, L2, 0, -R2, 0, L2, 0, R2, 0, -L2,0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 0, -L2, 0, R2, 0, -L2, 0, -R2, 0, L2, 0, R2}(1+j)/
{square root over (2)}; where
L2 is expressed as {M, -1, M, -1, -M, -1, M}, is expressed as {-M,
1, M, 1, -M, 1, -M}, -L2 is expressed as {-M, 1, -M, 1, M, 1, -M},
and -R2 is expressed as {M, -1, -M, -1, M, -1, M}.
In the foregoing technical solution, the 320-MHz bandwidth has 4096
tones in total. When the periodicity included in the short training
field is 1.6 .mu.s, the short training sequence may be expressed as
S.sub.-2024:8:2024, where -2024 indicates a subscript of a starting
tone, 2024 indicates a subscript of an ending tone, 8 indicates a
spacing, and -2024:8:2024 indicates starting with a tone whose
subscript is -2024 and ending with a tone whose subscript is 2024,
with a spacing of 8 tones in between. On other tones, a
frequency-domain sequence value is 0. Therefore, the values given
by the foregoing short training sequence each correspond to a
frequency-domain sequence value that starts with a tone whose
subscript is -2024 and ends with a tone whose subscript is 2024,
with a spacing of 8 tones in between. L2 and R2 are sequences
related to a short training sequence corresponding to 80 MHz and
the periodicity of 1.6 .mu.s. Therefore, the 320-MHz short training
sequence can be compatible with the 80-MHz short training sequence.
In addition, the 320-MHz short training sequence can support
automatic gain control on a high-bandwidth (the bandwidth is
greater than 160 MHz) channel. In addition, it is verified through
simulation that these short training sequences have comparatively
small peak-to-average power ratios, and therefore can support
automatic gain control on a high-bandwidth channel and can improve
an estimation effect for an automatic gain control circuit at a
receive end, thereby reducing a receive bit error rate.
With reference to the first aspect, in some implementations of the
first aspect, the bandwidth of the target channel is 320 MHz; and
when the periodicity included in the short training field is 1.6
.mu.s, the short training sequence is expressed as follows:
{L4, 1, R4, 0, L4, -1, -R4}(1+j)/ {square root over (2)}; or
{-L4, -1, -R4, 0, -L4, 1, R4}(1+j)/ {square root over (2)}; or
{L4, 0, R4, 0, L4, 0, -R4}(1+j)/ {square root over (2)}; or
{-L4, 0, -R4, 0, -L4, 0, R4}(1+j)/ {square root over (2)}; or
{L4, 0, R4, 0, L4, -1, -R4}(1+j)/ {square root over (2)}; or
{-L4, 0, -R4, 0, -L4, 1, R4}(1+j)/ {square root over (2)}; or
{L4, 0, --R4, 0, L4, 1, R4}(1+j)/ {square root over (2)}; or
{-L4, 0, R4, 0, -L4, -1, -R4}(1+j)/ {square root over (2)}; or
{L4, 1, R4, 0, L4, 0, -R4}(1+j)/ {square root over (2)}; or
{-L4, -1, -R4, 0, -L4, 0, R4}(1+j)/ {square root over (2)},
where
L4 is expressed as {M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1,
-M};
R4 is expressed as {-M, 1, -M, 1, M, 1,-M, 0, -M, 1, M, 1, -M, 1,
-M};
-L4 is expressed as {-M, 1, -M, 1, M, 1, -M, 0, M, -1, -M, -1, M,
-1, M}; and
-R4 is expressed as {M, -1, M, -1, -M, -1, M, 0, M, -1, -M, -1, M,
-1, M}.
In the foregoing technical solution, the 320-MHz bandwidth has 4096
tones in total. When the periodicity included in the short training
field is 1.6 .mu.s, the short training sequence may be expressed as
S.sub.-2040:8:2040, where -2040 indicates a subscript of a starting
tone, 2040 indicates a subscript of an ending tone, 8 indicates a
spacing, and -2040:8:2040 indicates starting with a tone whose
subscript is -2040 and ending with a tone whose subscript is 2040,
with a spacing of 8 tones in between. On other tones, a
frequency-domain sequence value is 0. Therefore, the values given
by the foregoing short training sequence each correspond to a
frequency-domain sequence value that starts with a tone whose
subscript is -2040 and ends with a tone whose subscript is 2040,
with a spacing of 8 tones in between. L4 and R4 are sequences
related to a short training sequence corresponding to 160 MHz and
the periodicity of 1.6 .mu.s. Therefore, the 320-MHz short training
sequence can be compatible with the 160-MHz short training
sequence. In addition, the 320-MHz short training sequence can
support automatic gain control on a high-bandwidth (the bandwidth
is greater than 160 MHz) channel. In addition, it is verified
through simulation that these short training sequences have
comparatively small peak-to-average power ratios, and therefore can
support automatic gain control on a high-bandwidth channel and can
improve an estimation effect for an automatic gain control circuit
at a receive end, thereby reducing a receive bit error rate.
According to a second aspect, a short training field sending
apparatus is provided. The apparatus includes: a determining
module, configured to determine a short training sequence; and a
sending module, configured to send a short training field on a
target channel, where the short training field is obtained by
performing inverse fast Fourier transformation IFFT on the short
training sequence, and a bandwidth of the target channel is greater
than 160 MHz.
According to a third aspect, a short training field sending
apparatus is provided. The apparatus includes: a processor,
configured to determine a short training sequence; and a
transceiver, configured to send a short training field on a target
channel, where the short training field is obtained by performing
inverse fast Fourier transformation IFFT on the short training
sequence, and a bandwidth of the target channel is greater than 160
MHz.
According to a fourth aspect, a processor is provided, including an
input circuit, an output circuit, and a processing circuit. The
processing circuit is configured to receive a signal by using the
input circuit, and transmit a signal by using the output circuit,
so that the processor performs the method according to any one of
the first aspect or the possible implementations of the first
aspect.
During specific implementation, the processor may be a chip, the
input circuit may be an input pin, the output circuit may be an
output pin, and the processing circuit may be a transistor, a gate
circuit, a trigger, various logic circuits, or the like. An input
signal received by the input circuit may be received and input by,
for example, but not limited to, a receiver. A signal output by the
output circuit may be output to, for example, but not limited to, a
transmitter, and transmitted by the transmitter. In addition, the
input circuit and the output circuit may be a same circuit, and the
circuit serves as the input circuit and the output circuit at
different moments. Specific implementations of the processor and
various circuits are not limited in this embodiment of this
application.
According to a fifth aspect, a communications device is provided,
including a processor, and optionally, further including a memory.
The memory is coupled to the processor, and the processor is
configured to perform the method according to any one of the first
aspect or the possible implementations of the first aspect.
Optionally, there are one or more processors, and there are one or
more memories.
Optionally, the memory may be integrated with the processor, or the
memory and the processor are disposed separately.
During specific implementation, the memory may be a non-transitory
memory, for example, a read-only memory (ROM). The memory and the
processor may be integrated on a same chip, or may be separately
disposed on different chips. A type of the memory and a manner of
disposing the memory and the processor are not limited in this
embodiment of this application.
Optionally, the processor includes at least one circuit configured
to determine a short training sequence, and includes at least one
circuit configured to transmit the short training field by using
the transmitter.
The processor in the fifth aspect may be a chip. The processor may
be implemented by hardware or software. When the processor is
implemented by hardware, the processor may be a logic circuit, an
integrated circuit, or the like. When the processor is implemented
by software, the processor may be a general-purpose processor, and
is implemented by reading software code stored in a memory. The
memory may be integrated in the processor, or may be located
outside the processor and exist independently.
According to a sixth aspect, a computer program is provided. When
the computer program is executed by a computer, the computer
program is used to perform the method according to any one of the
first aspect or the possible implementations of the first aspect.
The computer program may be entirely or partially stored in a
storage medium packaged with a processor, or may be partially or
entirely stored in a memory not packaged with a processor.
According to a seventh aspect, a computer-readable storage medium
is provided. The computer-readable storage medium stores a computer
program. The computer program includes at least one segment of
code. The at least one segment of code may be executed by a
computer, to control the computer to perform the method according
to any one of the first aspect or the possible implementations of
the first aspect.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a communications system to which a
short training field sending method according to an embodiment of
this application is applicable;
FIG. 2 is an internal structural diagram of a wireless access point
to which an embodiment of this application is applicable;
FIG. 3 is an internal structural diagram of a subscriber station to
which an embodiment of this application is applicable;
FIG. 4 is a schematic diagram of a VHT frame structure in
802.11ac;
FIG. 5 is a schematic diagram of a short training field sending
method according to an embodiment of this application;
FIG. 6 is a schematic diagram of constructing an HE-STF by using an
M-sequence;
FIG. 7 is a schematic block diagram of a short training field
sending apparatus according to an embodiment of this application;
and
FIG. 8 is a schematic structural diagram of a network device
according to an embodiment of this application.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
The following describes the technical solutions in this application
with reference to the accompanying drawings.
The technical solutions in the embodiments of this application may
be applied to various communications systems, for example, a
wireless local area network (WLAN) communications system, a global
system for mobile communications (GSM) system, a code division
multiple access (CDMA) system, a wideband code division multiple
access (WCDMA) system, a general packet radio service (GPRS)
system, a long term evolution (LTE) system, an LTE frequency
division duplex (FDD) system, LTE time division duplex (TDD)
system, a universal mobile telecommunications system (UMTS), a
worldwide interoperability for microwave access (WiMAX)
communications system, a 5th generation (5G) system, or new radio
(NR) system.
In the following example descriptions, only a WLAN system is used
as an example to describe an application scenario and a method in
the embodiments of this application.
Specifically, the embodiments of this application may be applied to
a wireless local area network (WLAN), and the embodiments of this
application is applicable to any protocol of Institute of
Electrical and Electronics Engineers (IEEE) 802.11 series protocols
currently used for the WLAN. The WLAN may include one or more basic
service sets (BSS), and a network node in the basic service set
includes an access point (AP) and a station (STA).
Specifically, in the embodiments of this application, an initiation
device and a response device each may be a subscriber station (STA)
on the WLAN. The subscriber station may also be referred to as a
system, a subscriber unit, an access terminal, a mobile station, a
mobile console, a remote station, a remote terminal, a mobile
device, a user terminal, a terminal, a wireless communications
device, a user agent, a user apparatus, or user equipment (UE). The
STA may be a cellular phone, a cordless phone, a session initiation
protocol (SIP) phone, a wireless local loop (WLL) station, a
personal digital assistant (PDA), a handheld device with a wireless
local area network (for example, Wi-Fi) communication function, a
wearable device, a computing device, or another processing device
connected to a wireless modem.
Alternatively, in the embodiments of this application, the
initiation device and the response device each may be an AP on the
WLAN. The AP may be configured to communicate with an access
terminal through a wireless local area network, and transmit data
of the access terminal to a network side, or transmit data from the
network side to the access terminal.
For ease of understanding the embodiments of this application, a
communications system shown in FIG. 1 is first used as an example
to describe in detail a communications system to which the
embodiments of this application are applicable. In a scenario shown
in FIG. 1, the system may be a WLAN system. The WLAN system in FIG.
1 may include one or more APs and one or more STAs. In FIG. 1, one
AP and three STAs are used as examples. The AP and the STAs may
wirelessly communicate with each other by using various standards.
For example, wireless communication may be performed between the AP
and the STAs by using a single-user multiple-input multiple-output
(SU-MIMO) technology or a multi-user multiple-input multiple-output
(MU-MIMO) technology.
The AP is also referred to as a wireless access point, a hotspot,
or the like. The AP is an access point for a mobile subscriber to
access a wired network, and is mainly deployed in a home, a
building, or a campus, or may be deployed outdoors. The AP is
equivalent to a bridge that connects the wired network and a
wireless network. A main function of the AP is to connect various
wireless network clients, and then connect the wireless network to
the Ethernet. Specifically, the AP may be a terminal device or a
network device with a wireless fidelity (Wi-Fi) chip. Optionally,
the AP may be a device that supports a plurality of WLAN standards
such as 802.11. FIG. 2 is an internal structural diagram of an AP
product. The AP may have a plurality of antennas or a single
antenna. In FIG. 2, the AP includes a physical layer (PHY)
processing circuit and a media access control (MAC) layer
processing circuit. The physical layer processing circuit may be
configured to process a physical layer signal, and the MAC layer
processing circuit may be configured to process a MAC layer signal.
The 802.11 standard focuses on a PHY and a MAC layer, and the
embodiments of this application focus on protocol design on the MAC
layer and the PHY.
A STA product is usually a terminal product supporting 802.11
series standards, for example, a mobile phone or a notebook
computer. FIG. 3 is a structural diagram of a STA with a single
antenna. In an actual scenario, the STA may alternatively have a
plurality of antennas, and may be a device with more than two
antennas. In FIG. 3, the STA may include a physical layer (PHY)
processing circuit and a media access control (MAC) layer
processing circuit. The physical layer processing circuit may be
configured to process a physical layer signal, and the MAC layer
processing circuit may be configured to process a MAC layer
signal.
To greatly increase a service transmission rate of a WLAN system,
in the IEEE 802.11ax standard, an orthogonal frequency division
multiple access (OFDMA) technology is further used based on an
existing orthogonal frequency division multiplexing (OFDM)
technology. The OFDMA technology enables a plurality of nodes to
simultaneously transmit and receive data, thereby achieving a
multi-station diversity gain.
During evolution from 802.11a to 802.11g, 802.11n, 802.11ac, and
802.11ax, available frequency bands include 2.4 gigahertz (GHz) and
5 GHz. As a quantity of open frequency bands increases, a maximum
channel bandwidth supported by 802.11 is extended from 20 megahertz
(MHz) to 40 MHz and then to 160 MHz. In 2017, the US Federal
Communications Commission (FCC) opened a new free 6-GHz frequency
band (5925-7125 MHz), and workers of the 802.11ax standard extended
an operating range of 802.11ax devices from 2.4 GHz and 5 GHz to
2.4 GHz, 5 GHz, and 6 GHz in the 802.11ax project authorization
requests (PAR). Because an available bandwidth of the newly opened
6-GHz frequency band is higher, it can be predicted that a channel
bandwidth greater than 160 MHz is to be supported in evolution of a
next-generation standard after 802.11ax.
Each generation of mainstream 802.11 protocol is compatible with
legacy stations. For example, a frame structure in 802.11a for an
earliest generation of mainstream Wi-Fi starts with a preamble, and
includes a legacy-short training field (L-STF), a legacy-long
training field (L-LTF), and a legacy-signal field (L-SIG). For
compatibility with legacy stations, a frame structure in subsequent
802.11 and 802.11ax that is being finalized starts with a legacy
preamble. The legacy preamble is followed by a signal field, a
short training field, and a long training field that are newly
defined for each generation. The short training field (STF) after
the legacy preamble is referred to as an extremely high
throughput-short training field (EHT-STF) for differentiation from
the L-STF. When transmission is performed at a channel bandwidth
greater than 20 MHz, the L-STF is replicated and then transmitted
on every 20-MHz channel bandwidth. These EHT-STFs introduced after
802.11a are separately defined as new sequences for a channel
bandwidth greater than 20 MHz. For example, for an STF defined in
802.11ac, that is, a very high throughput-short training field
(VHT-STF), 20-MHz, 40-MHz, 80-MHz, and 160-MHz sequences are
separately defined, as shown in FIG. 4. FIG. 4 is a schematic
diagram of a VHT frame structure in 802.11ac. Similarly, a high
efficiency-short training field (HE-STF) defined in 802.11ax also
supports a maximum channel bandwidth of 160 MHz. FIG. 4 includes a
legacy-training field (L-TF), a duplicate legacy-training field
(Dup L-TF), a legacy-signal field (L-SIG), a duplicate
legacy-signal field (Dup L-SIG), a very high throughput-signal
field-A (VHT-SIG-A), a duplicate very high throughput-signal
field-A (Dup VHT-SIG-A), a very high throughput-short training
field (VHT-STF), a very high throughput-long training field
(VHT-LTF), a very high throughput-signal field-B (VHT-SIG-B), and
very high throughput data (VHT Data).
According to stipulations of a protocol, a time-domain waveform of
the HE-STF includes five repetitions, and is mainly used to enhance
an estimation of an automatic gain control (AGC) circuit in
multiple-input multiple-output (MIMO) transmission; therefore, it
is required that a smaller peak-to-average power ratio (PAPR) of a
sequence should be better. As described above, a next-generation
protocol of 802.11 is expected to support a channel bandwidth
greater than 160 MHz.
Therefore, a new short training sequence needs to be designed for a
new channel bandwidth. In view of this, for a new channel
bandwidth, this application proposes a short training sequence
design corresponding to a next-generation STF.
For ease of understanding the embodiments of this application, the
following first briefly describes several nouns or terms used in
this application.
1. Tone: A wireless communication signal has a limited bandwidth.
An OFDM technology may be used to divide a channel bandwidth into a
plurality of frequency components within the bandwidth based on a
specific frequency spacing. These components are referred to as
tones.
2. Short Training Sequence
The short training sequence is mainly used for signal detection,
automatic gain control (AGC), symbol timing acquisition, coarse
frequency offset estimation, and the like. Different sequences may
be defined for different maximum channel bandwidths. For example,
the HE-STF defined in 802.11ax supports a maximum channel bandwidth
of 160 MHz. This application focuses on a channel bandwidth greater
than 160 MHz, therefore, for differentiation, is referred to as an
EHT-STF in the embodiments of this application. It should be
understood that the EHT-STF is used to represent a short training
field for a bandwidth greater than 160 MHz, and a specific name of
the EHT-STF does not limit the protection scope of the embodiments
of this application.
The short training sequence may be constructed based on an
M-sequence. For example, it can be learned from the 802.11.ax
standard that a high efficiency-short training sequence (HES-STF)
is constructed by performing multiplexing, phase rotation, and
combination based on the M-sequence. The M-sequence is a most basic
pseudo-noise sequence (PN sequence) currently used in a CDMA
system. The M-sequence is short for a maximum-length linear
feedback shift register sequence. The M-sequence is defined as
M={-1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1} in the
802.11.ax standard.
It should be noted that a specific name of the M-sequence does not
limit the protection scope of the embodiments of this application.
For example, the M-sequence may also be referred to as a
frequency-domain sequence.
3. Peak-to-Average Power Ratio
The peak-to-average power ratio (PAPR) may be a ratio of an
instantaneous peak power of continuous signals to an average signal
power within a symbol, and may be expressed by using the following
formula:
.times..function..function..function. ##EQU00001## where
X.sub.i indicates a time-domain discrete value of a sequence;
max(X.sub.i.sup.2) indicates a maximum value of a square of the
time-domain discrete value; and
mean(X.sub.i.sup.2) indicates an average value of the square of the
time-domain discrete value.
According to stipulations of a protocol, a time-domain waveform of
an HE-STF includes five repetitions, and is mainly used to enhance
an AGC estimation in MIMO transmission; therefore, it is required
that a smaller PAPR of a sequence should be better.
It should be noted that, in the embodiments of this application,
the "protocol" may be a standard protocol in the communications
field, for example, may include an LTE protocol, an NR protocol, a
WLAN protocol, and a related protocol applied to a future
communications system. This is not limited in this application.
It should be further noted that, in the embodiments of this
application, "pre-obtaining" may include being indicated by a
network device through signaling, or being predefined, for example,
being defined in a protocol. The "predefining" may be implemented
by prestoring corresponding code or a table on a device (for
example, including a terminal device and a network device), or in
another manner that may be used to indicate related information. A
specific implementation thereof is not limited in this application.
For example, the predefining may mean being defined in a
protocol.
It should be further noted that "storing" in the embodiments of
this application may mean being stored in one or more memories. The
one or more memories may be separately disposed, or may be
integrated in an encoder, a decoder, a processor, or a
communications apparatus. Alternatively, some of the one or more
memories may be separately disposed, and some of the one or more
memories are integrated in a decoder, a processor, or a
communications apparatus. A type of the memory may be a storage
medium in any form. This is not limited in this application.
It should be further noted that, in the embodiments of this
application, one of "of (of)", " relevant", and "corresponding "
may be used sometimes. It should be noted that expressed meanings
are consistent when differences are not emphasized.
It should be further noted that, in the following embodiments,
first, second, and third are merely intended to distinguish between
different objects, and should not constitute any limitation on this
application, for example, are intended to distinguish between
different channel bandwidths.
It should be further noted that "and/or" describes an association
relationship for describing associated objects and represents that
three relationships may exist. For example, A and/or B may
represent the following three cases: Only A exists, both A and B
exist, and only B exists. The character "/" generally indicates an
"or" relationship between the associated objects. "At least one"
means one or more. Similar to "A and/or B", "at least one of A and
B" describes an association relationship for describing associated
objects and represents that three relationships may exist. For
example, at least one of A and B may represent the following three
cases: Only A exists, both A and B exist, and only B exists. The
following describes in detail the technical solutions provided in
this application with reference to the accompanying drawings.
It should be understood that the technical solutions in this
application may be applied to a wireless communications system, for
example, the wireless communications system shown in FIG. 1. FIG. 5
is a schematic block diagram of a short training field sending
method according to an embodiment of this application. The method
200 shown in FIG. 5 includes step 210 and step 220.
Step 210: Determine a short training sequence.
Step 220: Send a short training field on a target channel, where
the short training field is obtained by performing inverse fast
Fourier transformation IFFT on the short training sequence, and a
bandwidth of the target channel is greater than 160 MHz.
In this embodiment of this application, for differentiation from a
legacy-short training field, the short training field corresponding
to the bandwidth of the target channel is denoted as an EHT-STF. It
should be understood that the EHT-STF is used to represent a short
training field corresponding to a bandwidth greater than 160 MHz,
and a specific name of the EHT-STF does not limit the protection
scope of this embodiment of this application.
In this embodiment of this application, the bandwidth of the target
channel is greater than 160 MHz. In this embodiment of this
application, an example in which the bandwidth of the target
channel is 240 MHz and an example in which the bandwidth of the
target channel is 320 MHz are used for description. It should be
understood that this embodiment of this application is not limited
thereto. For example, the bandwidth of the target channel may be
alternatively 200 MHz or 280 MHz.
Example 1: The bandwidth of the target channel is 240 MHz.
The EHT-STF is obtained by performing IFFT transformation on a
frequency-domain sequence of the EHT-STF. In this application, for
ease of description, the frequency-domain sequence of the EHT-STF
is denoted as a short training sequence S (sequence), the EHT-STF
may include a plurality of periods, and duration of each period may
be 0.8 .mu.s or 1.6 .mu.s. For brevity, in this embodiment of this
application, the duration of the period included in the EHT-STF is
denoted as a periodicity. In this embodiment of this application, a
scenario in which the periodicity is 0.8 .mu.s and a scenario in
which the periodicity is 1.6 .mu.s are used to describe the EHT-STF
for the bandwidth of the target channel.
Scenario 1: The periodicity is 0.8 .mu.s.
In this embodiment of this application, a short training sequence S
corresponding to a 240-MHz EHT-STF with a periodicity of 0.8 .mu.s
may be determined by using at least the following three
methods.
The 240-MHz bandwidth has 1024.times.3=3072 tones in total. There
are 12 guard tones on a left edge, 11 guard tones on a right edge,
and five direct-current tones in the middle of the bandwidth. In
addition, when the periodicity included in the short training field
is 0.8 .mu.s, the short training sequence corresponding to the
240-MHz EHT-STF may be expressed as S.sub.-1520:16:1520, where
-1520 indicates a subscript of a starting tone, 1520 indicates a
subscript of an ending tone, 16 indicates a spacing, and
-1520:16:1520 indicates starting with a tone whose subscript is
-1520 and ending with a tone whose subscript is 1520, with a
spacing of 16 tones in between. On other tones, a frequency-domain
sequence value is 0.
Method 1
Determine, based on a frequency-domain sequence HES of a reference
channel, the short training sequence S corresponding to the 240-MHz
EHT-STF with the periodicity of 0.8 .mu.s.
For the HES, the 802.11ax standard defines a frequency-domain value
HES.sub.a:b:c of the HE-STF, where a indicates a subscript of a
starting tone, c indicates a subscript of an ending tone, b
indicates a spacing, and a:b:c indicates starting with a tone a and
ending with a tone c, with a spacing of b tones in between. On
other tones, an HES value is 0. During sending, inverse Fourier
transformation is performed on a frequency-domain value to obtain a
time-domain waveform.
For example, a bandwidth of the reference channel is 80 MHz.
Optionally, the short training sequence S corresponding to the
EHT-STF with the periodicity of 0.8 .mu.s and the channel bandwidth
of 240 MHz may be expressed as follows:
{L1, 1, -R1, 1, -L1, 0, R1, 0, -L1, 0, -R1}(1+j)/ {square root over
(2)}; or
{-L1.-1, R1, -1, L1, 0, -R1, 0, L1, 0, R1}(1+j)/ {square root over
(2)}; or
{L1, 1, -R1, 1, -L1, 0, -R1, 1, L1, 1, R1}(1+j)/ {square root over
(2)}; or
{-L1, -1, R1, 1, L1, 0, R1, -1 -L1, -1, --R1}(1+j)/ {square root
over (2)}; or
{L1, 1, -R1, 1, -L1, 0, R1, 1, -L1, 0, -R1}(1+j)/ {square root over
(2)}; or
{-L1, -1, R1, -1 L1, 0, -1, -1, L1, 0, R1}(1+j)/ {square root over
(2)}; or
{L1, 0, -R1, 0, -L1, 0, R1, -1, -L1, 0, -R1,}(1+j)/ {square root
over (2)}; or
{-L1, 0, R1, 0, L1, 0, -R1, 1, L1, 0, R1}(1+j)/ {square root over
(2)}; or
{L1, 1, -R1, 0, -L1, 0, R1, -1, -L1, 0, -R1}(1+j)/ {square root
over (2)}; or
{-L1, -1, R1, 0, L1, 0, -R1, 1, L1, 0, R1}(1+j)/ {square root over
(2)}; or
L1=HES.sub.Left 1 {square root over (2)}/(1+j)=HES.sub.-496:16:-16
{square root over (2)}/(1+j), R1=HES.sub.Right 1 {square root over
(2)}/(1+j) =HES.sub.16:16:496 {square root over (2)}/(1+j);
HES.sub.Left 1 is a part of HES.sub.-496:16:496 on the left of a
tone 0, and HES.sub.Right 1 is a part of HES.sub.-496:16:496 on the
right of the tone 0;
HES.sub.-496:16:496 is an HES corresponding to 80 MHz and the
periodicity of 0.8 .mu.s; and
L1 is expressed as {M, 1, -M}, R1 is expressed as {-M, 1, -M}, -L1
is expressed as {-M, -1, M}, and -R1 is expressed as {M, -1,
M}.
As described above, the short training sequence corresponding to
the 240-MHz EHT-STF may be expressed as S.sub.-1520:16:1520.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -1520 and ends with a tone
whose subscript is 1520, with a spacing of 16 tones in between.
It should be noted that, in this embodiment of this application, L
(for example, L1, L2, L3, and L4) and R (for example, R1, R2, R3,
and R4), or HES.sub.Left (for example, HES.sub.Left 1 and
HES.sub.Left 2) and HES.sub.Right (for example, HES.sub.Right 1 and
HES.sub.Right 2) are used to indicate a part on the left of the
tone 0 and a part on the right of the tone 0. Specifically, L1
indicates a part, on the left of the tone 0, of the HES
corresponding to 80 MHz and the periodicity of 0.8 .mu.s, and R1
indicates a part, on the right of the tone 0, of the HES
corresponding to 80 MHz and the periodicity of 0.8 .mu.s; L2
indicates a part, on the left of the tone 0, of an HES
corresponding to 80 MHz and the periodicity of 1.6 .mu.s, and R2
indicates a part, on the right of the tone 0, of the HES
corresponding to 80 MHz and the periodicity of 1.6 .mu.s; L3
indicates a part, on the left of the tone 0, of an HES
corresponding to 160 MHz and the periodicity of 0.8 .mu.s, and
R.sub.3 indicates a part, on the right of the tone 0, of the HES
corresponding to 160 MHz and the periodicity of 0.8 .mu.s; L4
indicates a part, on the left of the tone 0, of an HES
corresponding to 160 MHz and the periodicity of 1.6 .mu.s, and
R.sub.4 indicates a part, on the right of the tone 0, of the HES
corresponding to 160 MHz and the periodicity of 1.6 .mu.s. In
addition, L=HES.sub.Left {square root over (2)}/(1+j), and
R=HES.sub.Right. e,rad 2/(1+J).
It should be further noted that L (for example, L1, L2, L3, and
14), R (for example, R1, R2, R3, and R4), and the like are only
used to indicate a part on the left of the tone 0 and a part on the
right of the tone 0, and names thereof (for example, L1, L2, L3,
L4, R1, R2, R3, and R4) do not limit the protection scope of this
embodiment of this application.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 0.8 .mu.s and
the channel bandwidth of 240 MHz may be expressed as any one of the
foregoing io expressions.
It can be learned from the foregoing that, by using the method 1,
the short training sequence S corresponding to the 240-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained through
transformation based on an HES specified in a standard.
Method 2
Obtain, through transformation based on an M-sequence, the short
training sequence S corresponding to the 240-MHz EHT-STF with the
periodicity of 0.8 .mu.s.
Specifically, L1 expressed as {M, 1, -M}, R1 expressed as {-M, 1,
-M}, -L.sub.1 expressed as {-M, -1, M}, and -R1 expressed as {M,
-1, M} are substituted, and it can be learned that the short
training sequence S corresponding to the 240-MHz EHT-STF with the
periodicity of 0.8 .mu.s may be expressed as follows:
{M, 1, -M, 1, M, -1, M, 1, -M, -1, M, 0, -M, 1, -M, 0, -M, -1, M,
0, M, -1, M}. (1+j)/ {square root over (2)}; or
{-M, -1, M, -1, -M, 1, -M, -1, M, 1, -M, 0, M, -1, M, 0, M, 1, -M,
0, -M, 1, -M}. (1+j)/ {square root over (2)}; or
{M, 1, -M, 1, M, -1, M, -1, -M, -1, M, 0, M, -1, M, 1, M, 1, -M, 1,
-M, 1, -M}. (1+j)/ {square root over (2)}; or
{-M, -1, M, -1, -M, 1, -M, 1, M, 1, -M, 0, -M, 1, -M, -1, -M, -1,
M, -1, M, -1, M}. (1+j)/ {square root over (2)}; or
{M, 1, -M, 1, M, -1, M, 1, -M, -1, M, 0, -M, 1, -M, 1, -M, -1, M,
0, M, -1, M}. (1+j)/ {square root over (2)}; or
{-M, -1, M, -1, -M, 1, -M, -1, M, 1, -M, 0, M, -1, M, -1, M, 1, -M,
0, -M, 1, -M}. (1+j)/ {square root over (2)}; or
{M, 1, -M, 0, M, -1, M, 0, -M, -1, M, 0, -M, 1, -M, -1, -M, -1, M,
0, M, -1, M}. (1+j)/ {square root over (2)}; or
{-M, -1, M, 0, M, 1, -M, 0, M, 1, -M, 0, M, -1, M, 1, M, 1, -M, 0,
-M, 1, -M}. (1+j)/ {square root over (2)}; or
{M, 1, -M, 1, M, -1, M, 0, -M, 1, -M, 0, -M, -1, -M, -1, M, 1, -M,
0, -M, 1, -M}. (1+j)/ {square root over (2)}; or
{-M, -1, M, -1, -M, 1, -M, 0, -M, 1, M, 0, M, 1, M, 1, M, 1, -M, 0,
-M, 1, -M}. (1+j)/ {square root over (2)}.
Similarly, as described above, the short training sequence
corresponding to the 240-MHz EHT-STF may be expressed as
S.sub.-1520:16:1520. Therefore, the values given by the foregoing
short training sequence each correspond to a frequency-domain
sequence value that starts with a tone whose subscript is -1520 and
ends with a tone whose subscript is 1520, with a spacing of 16
tones in between.
It should be noted that the short training sequence S corresponding
to the EHT-STF with the periodicity of 0.8 .mu.s and the channel
bandwidth of 240 MHz may be expressed as any one of the foregoing
10 expressions.
It can be learned from the foregoing that, by using the method 2,
the short training sequence S corresponding to the 240-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained through
transformation based on the M-sequence.
Method 3
The short training sequence S corresponding to the EHT-STF in the
foregoing method 1 or method 2 is directly cached or stored
locally. When the short training sequence S corresponding to the
EHT-STF is to be used, the short training sequence S corresponding
to the EHT-STF may be directly obtained locally.
It should be understood that the foregoing three methods are merely
examples for description, and this application is not limited
thereto. Any method that can be used to obtain the 240-MHz EHT-STF
with the periodicity of 0.8 .mu.s falls within the protection scope
of this embodiment of this application.
The 240-MHz EHT-STF with the periodicity of 0.8 .mu.s may be
obtained through simulation calculation. For example, if the method
1 is used, the EHT-STF may be obtained through calculation based on
a stored HE-STF by using a corresponding formula. For another
example, if the method 2 is used, the EHT-STF may be obtained
through calculation based on a stored or protocol-specified
M-sequence by using a corresponding formula. Details are provided
below.
Specifically, in this embodiment of this application, the short
training sequence corresponding to the bandwidth of the target
channel may be designed based on a short training sequence for an
existing channel bandwidth (for example, the bandwidth of the
reference channel). For brevity, the short training sequence for
the bandwidth of the reference channel is referred to as a
reference short training sequence. Without loss of generality, the
following describes in detail a method for designing the short
training sequence S corresponding to the 240-MHz EHT-STF in this
embodiment of this application by using an example in which a
reference short training field is an HE-STF and a target short
training field is an EHT-STF.
Determining a short training sequence HES corresponding to an
HE-STF for the bandwidth of the reference channel may be
pre-obtaining a short training sequence HES, or directly using a
short training sequence HES that corresponds to an HE-STF for a
bandwidth of an existing reference channel and that is specified in
a standard. This is not limited in this embodiment of this
application. In this embodiment of this application, designing a
short training sequence for a higher channel bandwidth based on a
short training sequence for an existing channel bandwidth is mainly
considered.
According to this embodiment of this application, in consideration
of backward compatibility, a short training sequence for a higher
channel bandwidth, for example, a short training sequence S
corresponding to an EHT-STF, is designed based on a short training
sequence HES corresponding to an STF for an existing channel
bandwidth, for example, a short training sequence HES corresponding
to an HE-STF.
For ease of understanding, a design, in 802.11ax, of a short
training sequence HES corresponding to an HE-STF is first briefly
described.
FIG. 6 is a schematic diagram of constructing an HE-STF by using an
M-sequence. A diagram (1) in FIG. 6 is a repetition structure.
Specifically, a 20-MHz HE-STF is constructed by using one
M-sequence, a 40-MHz HE-STF is obtained by combining two 20-MHz
HE-STFs (that is, two M-sequences), and similarly, an 80-MHz HE-STF
is obtained by combining four 20-MHz HE-STFs. To ensure that the
HE-STF includes five repetitions in time domain and a PAPR of the
HE-STF is as small as possible, an additional parameter value and a
rotation factor may be used for adjustment and optimization, as
shown in a diagram (2) in FIG. 6. Specifically, a 20-MHz HE-STF is
constructed by using one M-sequence, a 40-MHz HE-STF is obtained by
combining two 20-MHz HE-STFs (that is, two M-sequences) that are
multiplied by a rotation factor C, and similarly, an 80-MHz HE-STF
is obtained by combining four 20-MHz HE-STFs that are multiplied by
the rotation factor. In addition, a parameter value A needs to be
inserted between every two M-sequences, to ensure that the HE-STF
includes five repetitions in time domain. An exception is that an
OFDM modulation scheme requires that a direct-current tone should
be 0. Therefore, a PAPR of the HE-STF can be minimized by
optimizing A and C. As shown in the diagram (2) in FIG. 6, the
rotation factor C includes {c1, c2, c3, c4, . . . }, and the
parameter value A includes {a1, a2, a3, a4, . . . }.
As described above, 802.11ax defines HE-STFs with two periodicities
based on different frame structures defined in 802.11ax, where the
periodicities are 0.8 .mu.s and 1.6 .mu.s. In addition, 802.11ax
supports four channel bandwidths: 20 MHz, 40 MHz, 80 MHz, and 160
MHz. Each bandwidth and periodicity correspond to one HE-STF.
Therefore, the HE-STF has eight frequency-domain values
HES.sub.a:b:c in total.
The following separately describes optimized frequency-domain
sequences for different channel in which a periodicity is 0.8 .mu.s
and a case in which a periodicity is 1.6 .mu.s.
Case 1: frequency-domain sequence of a 0.8-.mu.s HE-STF
A 0.8-.mu.s HE-STF with a channel bandwidth of 20 MHz has 256 tones
in total, and a subscript ranges from 127 to 128. A tone with a
subscript of 0 corresponds to a direct-current component, a tone
with a negative-number subscript corresponds to a frequency
component lower than the direct-current component, and a tone with
a positive-number subscript corresponds to a frequency component
higher than the direct-current component.
HES.sub.-112:16:112 may be expressed by using the following
formula: HES.sub.-112:16:112={M} {square root over (2)}/(1+j),
where HES.sub.0=0, and frequency-domain values of other tones are
0;
HES.sub.-112:16:112 indicates a frequency-domain sequence of the
20-MHz HE-STF, specifically, frequency-domain values of tones with
subscripts of -112, -96, -80, -64, -48, -32, -16, 0, 16, 32, 48,
64, 80, 96, and 112; and
the other tones are tones with remaining subscripts, within the
subscript range from -127 to 128, other than the tones with the
subscripts of -112, -96, -80, -64, -48, -32, -16, 0, 16, 32, 48,
64, 80, 96, and 112.
The foregoing formula is expanded as follows:
HES.sub.-112:16:112={-(1+j)/ {square root over (2)}, -(1+j)/
{square root over (2)}, -(1+j)/ {square root over (2)}, -(1+j)/
{square root over (2)}, -(1+j)/ {square root over (2)}, -(1+j)/
{square root over (2)}, -(1+j)/ {square root over (2)}, -(1+j)/
{square root over (2)}, -(1+j)/ {square root over (2)}, -(1+j)/
{square root over (2)}, -(1+j)/ {square root over (2)}, -(1+j)/
{square root over (2)}, -(1+j)/ {square root over (2)}, -(1+j)/
{square root over (2)}},
Therefore, the frequency-domain values of the tones with the
subscripts of -112, -96, -80, -64, -48, -32, -16, 0, 16, 32, 48,
64, 80, 96, and 112 are as follows:
-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j )/ {square root over (2)},
(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2
)}-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
and -(1+j)/ {square root over (2)}
It should be noted that, in this embodiment of this application,
expressions similar to HES.sub.-112:16:112 in formulas have similar
meanings. For brevity, details are not described again.
It should be further noted that, in this embodiment of this
application, in the following descriptions of formulas, unless
otherwise specified, frequency-domain values of tones with other
subscripts are all 0. For brevity, details are not described
again.
A 0.8-.mu.s HE-STF with a channel bandwidth of 40 MHz has 512 tones
in total, and a subscript ranges from -255 to 256.
HES.sub.-240:16:240 may be expressed by using the following
formula: HES.sub.-240:16:240={M, 0, -M}(1+j)/ {square root over
(2)}, where
HES.sub.-240:16:240 indicates a frequency-domain sequence of the
40-MHz HE-STF.
A 0.8-.mu.s HE-STF with a channel bandwidth of 80 MHz has 1024
tones in total, and a subscript ranges from -511 to 512.
HES.sub.-496:16:496 may be expressed by using the following
formula: HES.sub.-496:16:496={M, 1, -M, 0, -M, 1, -M}(1+j)/ {square
root over (2)}, where
HES.sub.-496:16:496 indicates a frequency-domain sequence of the
80-MHz HE-STF.
A 0.8-.mu.s HE-STF with a channel bandwidth of 160 MHz has 2048
tones in total, and a subscript ranges from -1023 to 1024.
HES.sub.-1008:16:1008 may be expressed by using the following
formula: HES.sub.-1008:16:1008={M, 1, -M, 0, -M, 1, -M, 0, -M, -1,
M, 0, -M, 1, -M}(1+j)/ {square root over (2)}, where
HES.sub.-1008:16:1008 indicates a frequency-domain sequence of the
160-MHz HE-STF.
Case 2: frequency-domain sequence of a 1.6-.mu.s HE-STF
A 1.6-.mu.s HE-STF with a channel bandwidth of 20 MHz has 256 tones
in total, and a subscript ranges from -127 to 128.
HES.sub.-112:8:112 may be expressed by using the following formula:
HES.sub.-112:8:112={M, 0, -M}(1+j)/-(1+j)/ {square root over (2)},
where HES.sub.0=0, and frequency-domain values of other tones are
0; and
similar to that in the case 1:
HES.sub.-112:8:112 indicates a frequency-domain sequence of the
20-MHz HE-STF, specifically, frequency-domain values of tones with
subscripts of -112, -104, -96, -88, -80, -72, -64, -56, -48, -40,
-32, -24, -16, -8, 0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88,
96, 104, and 112; and
the other tones are tones with remaining subscripts, within the
subscript range from -127 to 128, other than the tones with the
subscripts of -112, -104, -96, -88, -80, -72, -64, -56, -48, -40,
-32, -24, -16, -8, 0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88,
96, 104, and 112.
The foregoing formula is expanded as follows:
HES.sub.-112:8:112={-(1+j)/ {square root over (2)}, -(1+j)/ {square
root over (2)}, -(1+j)/ {square root over (2)}, (1+j)/ {square root
over (2)}, (1+j)/ {square root over (2)}, (1+j)/ {square root over
(2)}, -(1+j)/ {square root over (2)}, (1+j)/ {square root over
(2)}, (1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, 0, (1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
}.
Therefore, the frequency-domain values of the tones with the
subscripts of -112, -104, -96, -88, -80, -72, -64, -56, -48, -40,
-32, -24, -16, -8, 0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88,
96, 104, and 112 are as follows:
-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, 0, (1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, (1+j)/ {square root over (2)},
-(1+j)/ {square root over (2)}, -(1+j)/ {square root over (2)},
(1+j)/ {square root over (2)}, and -(1+j)/ {square root over
(2)},
It should be noted that, in this embodiment of this application,
expressions similar to HES.sub.-112:8:112 in formulas have similar
meanings. For brevity, details are not described again.
It should be further noted that, in this embodiment of this
application, in the following descriptions of formulas, unless
otherwise specified, frequency-domain values of tones with other
subscripts are all o. For brevity, details are not described
again.
A 1.6-.mu.s HE-STF with a channel bandwidth of 40MHz has 512 tones
in total, and a subscript ranges from -255 to 256.
HES.sub.-248:8:248 may be expressed by using the following formula:
HES.sub.-248:8:248={M, -1, -M, 0, M, -1, M}(1+j)/ {square root over
(2)}, where HES.sub..+-.248=0; and
HES.sub.-248:8:248 indicates a frequency-domain sequence of the
40-MHz HE-STF.
A 1.6-.mu.s HE-STF with a channel bandwidth of 80 MHz has 1024
tones in total, and a subscript ranges from -511 to 512.
HES.sub.-504:8:504 may be expressed by using the following formula:
HES.sub.-504:8:504 ={M, M, 1, M, 1, M, 0, M, 1, M, 1, M, 1,
M}(1+j)/ {square root over (2)}, where
HES.sub..+-.504 =0; and
HES.sub.-504:8:504 indicates a frequency-domain sequence of the
80-MHz HE-STF.
A 1.6-.mu.s HE-STF with a channel bandwidth of 160 MHz has 2048
tones in total, and a subscript ranges from -1023 to 1024.
HES.sub.-1016:8:1016 may be expressed by using the following
formula: HES.sub.-1016:8:1016={M, -1, M, -M, -1, M, 0, -M, 1, M, 1,
-M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1,
-M}(1+j)/ {square root over (2)}, where
HES.sub..+-.8=0, and HES.sub..+-.1016 =0; and
HES.sub.-1016:8:1016 indicates a frequency-domain sequence of the
160-MHz HE-STF.
In the foregoing formulas, a geometric meaning of (1+j)/ {square
root over (2)} on a complex plane is to rotate a value by
45.degree. counterclockwise and keep energy normalized. Similarly,
-(1+j)/ {square root over (2)} is to rotate a value by 225.degree.
counterclockwise. Therefore, HE-STFs for different channel
bandwidths are obtained based on the M-sequence, and it is ensured
that an optimized PAPR is achieved. Table 1 lists PAPRs of the
foregoing eight HE-STFs.
TABLE-US-00001 TABLE 1 PAPR 20 MHz 40 MHz 80 MHz 160 MHz 0.8 .mu.s
1.89 4.40 4.53 5.05 1.6 .mu.s 4.40 5.22 4.79 6.34
In this embodiment of this application, the rotation factor C and
the parameter set A are optimized, to design an EHT-STF for a
higher channel bandwidth (for example, the bandwidth of the target
channel).
Optionally, the rotation factor C and the parameter set A may be
optimized based on the 80-MHz HE-STF, to design the 240-MHz
EHT-STF.
Specifically, a channel with a bandwidth of 240 MHz may be
constructed by combining three 80-MHz channels. Before a design of
an EHT-STF for a channel supporting a bandwidth of 240 MHz is
described, a 240-MHz tone plan (tone plan) is first described.
As described above, a tone plan (tone plan) specified in 802.11ax
for a channel with a bandwidth of 80 MHz includes 1024 tones in
total, a subscript ranges from -511 to 512, and there are 12 guard
tones (guard tone) on a left edge of the bandwidth, 11 guard tones
on a right edge of the bandwidth, and five direct-current tones in
the middle of the bandwidth. The tone plan designed in this
application for the channel bandwidth of 240 MHz is obtained by
directly combining three existing 80-MHz tone plans, that is, tones
on a left edge, tones on a right edge, and direct-current tones in
the middle of each of the three 80 MHz are reserved. In this way,
the 240-MHz bandwidth has 1024.times.3=3072 tones in total, and
there are 12 guard tones on a left edge, 11 guard tones on a right
edge, and five direct-current tones in the middle of the
bandwidth.
Therefore, a frequency-domain sequence S is designed for the
240-MHz EHT-STF based on a frequency-domain sequence HES defined in
802.11ax for an 80-MHz HE-STF. As described above, the EHT-STF is
obtained by performing IFFT transformation on a frequency-domain
sequence of the EHT-STF, the EHT-STF may include a plurality of
periods, and duration of each period may be 0.8 .mu.s or 1.6 .mu.s.
Therefore, in this embodiment of this application, there may be two
periodicities: 0.8 .mu.s or 1.6 .mu.s.
When the periodicity is 0.8 .mu.s, the short training sequence S
corresponding to the 240-MHz EHT-STF may be expressed as follows:
S.sub.-1520:16:1520={c1L1, a1, c2R1, a2, c3L1, 0, c4R1, a3, c5L1,
a4, c6R1}(1+j)/ {square root over (2)} (1-1)
or
the formula may be expressed as follows:
S.sub.-1520:16:1520={c1HES.sub.Left 1, a1, c2HES.sub.Right 1, a2,
c3HES.sub.Left 1, 0, c4HES.sub.Right 1, a3, c5HES.sub.Left 1, a4,
c6HES.sub.Right 1}(1+j)/ {square root over (2)} (1-2)
or
when the periodicity is 1.6 .mu.s, the short training sequence S
corresponding to the 240-MHz EHT-STF may be expressed as follows:
S.sub.-1528:8:1528={c.sub.1L2, a.sub.1, c.sub.2R2, a.sub.2,
c.sub.3L2, 0, c.sub.4R2, a.sub.4, c.sub.6R2}(1+j)/ {square root
over (2)} (1-3)
or
the formula may be expressed as follows:
S.sub.-1528:8:1528={c1HES.sub.Left 2, a1, c2HES.sub.Right 2, a2,
c3HES.sub.Left 2, 0,c4HES.sub.Right 2, a3,c5HES.sub.Left 2, a4,
c6HES.sub.Right 2}(1+j)/ {square root over (2)} (1-4)
where
a value of a.sub.i is {-1, 0, 1}, and i=1, 2, 3, 4;
a value of c.sub.j is {-1, 1}, and j=1, 2, 3, 4, 5, 6;
S.sub.-1520:16:1520 indicates the frequency-domain sequence of the
240-MHz EHT-STF with the periodicity of 0.8 .mu.s;
S.sub.-1528:8:1528 indicates the frequency-domain sequence of the
240-MHz EHT-STF with the periodicity of 1.6 .mu.s;
HES.sub.Left 1is a part of HES-.sub.496:16:496 on the left of a
tone 0, and HES.sub.Right 1 is a part of HES-.sub.496:16:496 on the
right of the tone 0;
L1=HES.sub.Left 1 {square root over (2)}/(1+j), and
R1=HES.sub.Right 1 {square root over (2)}/(1+j);
HES.sub.Left 2 is a part of HES.sub.-504:8:504 on the left of the
tone 0, and HES.sub.Right 2 is a part of HES.sub.-504:8:504 on the
right of the tone 0; and
L2=HES.sub.Left 2 {square root over (2)}/(1+j), and
R2=HES.sub.Right 2 {square root over (2)}/(1+j).
It should be noted that any variation of the foregoing formulas
(1-1), (1-2), (1-3), and (1-4) falls within the protection scope of
this embodiment of this application. In this embodiment of this
application, for brevity, descriptions are provided in a form
similar to the formulas (1-1) and (1-3).
Therefore, in the scenario 1, that is, when the periodicity is 0.8
.mu.s, based on the frequency-domain sequence HES.sub.-496:16:496
defined in 802.11ax for the 80-MHz HE-STF with the periodicity of
0.8 .mu.s, a detailed design formula for the short training
sequence corresponding to the 240-MHz EHT-STF with the periodicity
of 0.8 .mu.s is as follows:
S.sub.-1520:16:1520=c.sub.1HES.sub.-496:16:-16, a.sub.1,
c.sub.2HES.sub.16:16:496, a.sub.2, c.sub.3HES.sub.-496:16:-16, 0,
c.sub.4HES.sub.16:16:496, a.sub.3, c.sub.5HES.sub.-496:16:-16,
a.sub.4, c.sub.6HES.sub.16:16:496}(1+j) (2-1)
where
a value of a.sub.i is {-1, 0, 1}, and i=1, 2, 3, 4;
a value of c.sub.j is {-1, 1,}, and j=1, 2, 3, 4, 5, 6;
S.sub.-1520:16:1520 indicates the frequency-domain sequence of the
240-MHz EHT-STF; and
HES.sub.-496:16:-16 is the part of HES.sub.-496:16:496 on the left
of the tone 0, and HES.sub.16:16:496 is the part of
HES.sub.-496:16:496 on the right of the tone 0.
For brevity, the foregoing formula may be alternatively designed as
follows: S.sub.-1520:16:1520=c.sub.1L.sub.1, a.sub.1, c.sub.2R1,
a.sub.2, c.sub.3L1, 0, c.sub.4R1, a.sub.4, c.sub.6R1}(1+j)/ {square
root over (2)} (2-2)
L1=HES.sub.-496:16:-16 {square root over (2)}/(1+j)={M, 1, -M};
and
R1=HES.sub.16:16:496 {square root over (2)}/(1+j)={-M, 1, -M}.
Therefore, when the short training sequence corresponding to the
240-MHz EHT-STF with the periodicity of 0.8 .mu.s is obtained by
using the method 1, the short training sequence may be obtained
based on the stored HES.sub.-496:16:-16 and HES.sub.16:16:496 by
using the formula (2-1). Alternatively, when the short training
sequence corresponding to the 240-MHz EHT-STF with the periodicity
of 0.8 .mu.s is obtained by using the method 2, the short training
sequence may be obtained based on the M-sequence by using the
formula (2-2).
The short training sequence corresponding to the 240-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained based on the
formula (2-1) or (2-2). In addition, simulation calculation is
performed, for example, a, and c, are adjusted, so that a PAPR
corresponding to the short training sequence corresponding to the
EHT-STF is less than or equal to a preset first threshold, to
obtain a sequence with comparatively good performance.
Specifically, inverse Fourier transformation and fivefold
over-sampling may be performed on S (that is, S.sub.-1520:16:1520)
to obtain a time-domain discrete value X of each sequence, and then
the PAPR is calculated based on the following formula (3):
.times..function..function..function. ##EQU00002##
Specifically, after 2.sup.6.times.3.sup.4=5184 exhaustive searches
are performed, all possible S.sub.-1520:16:1520 and corresponding
PAPR values may be obtained, and S.sub.-1520:16:1520 with a
smallest PAPR is finally obtained through comparison. Table 2 shows
a.sub.i and c.sub.i in 10 groups of optimal S when the short
training sequence S corresponding to the 240-MHz EHT-STF with the
periodicity of 0.8 .mu.s is designed based on the short training
sequence corresponding to the 80-MHz HE-STF with the periodicity of
0.8 .mu.s.
Setting a preset threshold (for example, the preset first
threshold) may be performing exhaustion on the parameter set A and
the parameter set C, and performing setting based on a minimum PAPR
value (for example, 10 groups of results with minimum PAPRs in
Table 2) obtained in an exhaustion process, or may be performing
setting comprehensively with reference to a minimum PAPR value
obtained in an exhaustion result, a property of a sequence, and the
like, or may be performing setting comprehensively with reference
to a minimum PAPR value obtained in an exhaustion result, a preset
parameter, and the like; or the preset threshold may be specified
in advance; or the preset threshold may be obtained based on a
plurality of experiment results, or the like.
TABLE-US-00002 TABLE 2 Values of parameter sets for the short
training sequence S corresponding to the 240-MHz EHT-STF with the
periodicity of 0.8 .mu.s Sequence number a.sub.1 a.sub.2 a.sub.3
a.sub.4 c.sub.1 c.sub.2 c.sub.3 c.sub.4 c.s- ub.5 c.sub.6 PAPR (dB)
1 1 1 0 0 1 -1 -1 1 -1 -1 4.8999 2 -1 -1 0 0 -1 1 1 -1 1 1 4.8999 3
1 -1 1 1 1 -1 -1 -1 1 1 4.9376 4 -1 1 -1 -1 -1 1 1 1 -1 -1 4.9376 5
1 1 1 0 1 -1 -1 1 -1 -1 4.959 6 -1 -1 -1 0 -1 1 1 -1 1 1 4.959 7 0
0 -1 0 1 -1 -1 1 -1 -1 4.966 8 0 0 1 0 -1 1 1 -1 1 1 4.966 9 1 0 -1
0 1 -1 -1 1 -1 -1 4.9725 10 -1 0 1 0 -1 1 1 -1 1 1 4.9725
The values of a.sub.i and c.sub.i in the obtained 10 groups of
results are separately substituted into the foregoing formula, and
it can be learned that the short training sequence corresponding to
the 240-MHz EHT-STF with the periodicity of 0.8 .mu.s may be
expressed as follows:
{L1, 1, -R1, 1, -L1, 0, R1, 0, -L1, 0, -R1}(1+j)/ {square root over
(2)}; or
{-L1, -1, R1, -1, L1, 0, -R1, 0, L1, 0, R1}(1+j)/ {square root over
(2)}; or
{L1, 1, -R1, -1, -L1, 0, -R1, 1, L1, 1, R1}(1+j)/ {square root over
(2)}; or
{-L1, -1, R1, 1, L1, 0, R1, -1, -L1, -1, -R1}(1+j)/ {square root
over (2)}; or
{L1, 1, -R1, 1, -L1, 0, R1, 1, -L1, 0, -R1}(1+j)/ {square root over
(2)}; or
{-L1, -1, R1, -1 L1, 0, -R1, -1, L1, 0, R1}(1+j)/ {square root over
(2)}; or
{L1, 0, -R1, 0, -L1, 0, R.sub.1, -1, L.sub.1, 0, -R1}(1+j)/ {square
root over (2)}; or
{-L1, 0, R1, 0, L1, 0, -R1, 1, L1, 0, R1}(1+j)/ {square root over
(2)}; or
{L1, 1, -R1, 0, -L.sub.1, 0, R1, -1, -L1, 0, R1i}(1+j)/ {square
root over (2)}; or
{-L1, -1, R1, 0, L1, 0, -R1, 1, L1, 0, R1}(1+j)/ {square root over
(2)}.
L1 expressed as {M, 1, -M}, R.sub.1 expressed as {-M, 1, -M}, -L1
expressed as {-M, -1, M}, and -R1 expressed as {M, -1, M} may be
substituted to obtain the short training sequence corresponding to
the 240-MHz EHT-STF with the periodicity of 0.8 .mu.s.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 0.8 .mu.s and
the channel bandwidth of 240 MHz may be expressed as any one of the
foregoing io expressions.
It can be learned from the foregoing that L1 and R1 are sequences
related to the short training sequence corresponding to the 80-MHz
short training field with the periodicity of 0.8 .mu.s. Therefore,
the 240-MHz short training sequence can be compatible with the
80-MHz short training sequence. In addition, the 240-MHz short
training sequence can support automatic gain control on a
high-bandwidth (the bandwidth is greater than 160 MHz) channel. In
addition, it is verified through simulation and comparison between
the PAPRs in Table 2 and the PAPRs in 802.11ax (Table 1) that these
short training sequences have comparatively small peak-to-average
power ratios, and therefore can support automatic gain control on a
high-bandwidth channel and can improve an estimation effect for an
automatic gain control circuit at a receive end, thereby reducing a
receive bit error rate. Therefore, the short training sequence
proposed for a high channel bandwidth in this solution of this
application can control a PAPR to be very small.
Scenario 2: The periodicity is 1.6 .mu.s.
Similarly, in this embodiment of this application, a short training
sequence S corresponding to a 240-MHz EHT-STF with a periodicity of
1.6 .mu.s may be determined by using at least the following three
methods.
The 240-MHz bandwidth has 1024.times.3=3072 tones in total. There
are 12 guard tones on a left edge, 11 guard tones on a right edge,
and five direct-current tones in the middle of the bandwidth. In
addition, when the periodicity included in the short training field
is 1.6 .mu.s, the short training sequence corresponding to the
240-MHz EHT-STF may be expressed as S.sub.-1528:8:1528, where -1528
indicates a subscript of a starting tone, 1528 indicates a
subscript of an ending tone, 8 indicates a spacing, and
-1528:8:1528 indicates starting with a tone whose subscript is
-1528 and ending with a tone whose subscript is 1528, with a
spacing of 8 tones in between. On other tones, a frequency-domain
sequence value is 0.
Method 1
Determine, based on a frequency-domain sequence HES for a bandwidth
of a reference channel, the short training sequence S corresponding
to the 240-MHz EHT-STF with the periodicity of 1.6 .mu.s.
For example, the bandwidth of the reference channel is 80 MHz.
Optionally, the short training sequence corresponding to the
EHT-STF with the periodicity of 1.6 .mu.s and the target channel
bandwidth of 240 MHz may be expressed as follows:
{L2, -1, -R2, -1, L2, 0, R2, 1, -L2, 1, 31 R2}(1+j)/ {square root
over (2)}; or
{-L2, 1, R2, 1, -L2, 0, -R2, -1, L2, -1, R2}(1+j)/ {square root
over (2)}; or
{L2, 0, -R2, -1, L2, 0, R2, 1, -L2, 1, -R2}(1+J)/ {square root over
(2)}; or
{-L2, 0, R2, 1, -L2, 0, -R2, -1, L2, -1, R2}(1+j)/ {square root
over (2)}; or
{L2, -1, -R2, -1, L2, 0, R2, 1, -L2, 0, -R2}(1+j)/ {square root
over (2)}; or
{-L2, 1, R2, 1, -L2, 0, -R2, -1, L2, 0, R2}(1+j)/ {square root over
(2)}; or
{L2, -1, -R2, -1, L2, 0, R2, 0, -L2, 1, -R2}(1+j)/ {square root
over (2)}; or
{-L2, 1, R2, 1, -L2, 0, -R2, 0, L2, -1, R2}(1+j)/ {square root over
(2)}; or
{L2, -1, -R2, 0, L2, 0, R2, 1, -L2, 1, -R2}(1+j)/ {square root over
(2)}; or
{-L2, 1, R2, 0, -L2, 0, -R2, -1, L2, -1, R2})1+j)/ {square root
over (2)}; or
L2=HES.sub.-504:8:-8 {square root over (2)}/(1+j)={M, -1, M, -1,
-M, -1, M}, and HES.sub.-504:8:-8 is a part of HES.sub.-504:8:504
on the left of a tone 0;
R2=HES.sub.8:8:504 {square root over (2)}/(1+j)={-M, 1, M, 1, -M,
1, -M}, and HES.sub.8:8:504 is a part of HES.sub.-504:8:504 on the
right of the tone 0;
HES.sub.-504:8:504 is a frequency-domain sequence corresponding to
80 MHz and the periodicity of 1.6 .mu.s; and
L2 is expressed as {M, -1, M, -1, -M, -1, M }, R2 is expressed as
{-M, 1, M, 1, -M, -M}, -L2={-M, 1, -M, 1, -M}, and -R2 is expressed
as {M, -1, -M, -1, M, -1, M}.
As described above, the short training sequence corresponding to
the 240-MHz EHT-STF may be expressed as S.sub.-1528:8:1528.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -1528 and ends with a tone
whose subscript is 1528, with a spacing of 8 tones in between.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 1.6 .mu.s and
the channel bandwidth of 240 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that, by using the method 1,
the short training sequence corresponding to the 240-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained through
transformation based on an HES specified in a standard.
Method 2
Obtain, through transformation based on an M-sequence, the short
training sequence S corresponding to the 240-MHz EHT-STF with the
periodicity of 1.6 .mu.s.
Specifically, L2 expressed as {M, -1, M, -1, -M, -1, M}, R2
expressed as {-M, 1, M, 1, -M, 1, =M}, -L2, ={-M, 1, -M, 1 M, 1,
-M}, and -R2 expressed as {M, -1, -M, -1, M, -1, M}. are
substituted, and it can be learned that the short training sequence
corresponding to the 240-MHz EHT-STF with the periodicity of 1.6
.mu.s may be expressed as follows:
{M, -1, M, -1, -M, -1, M, -1, M, -1, -M, -1, M, -1, M, -1, M, -1,
M, -1, -M, -1, M, 0, -M, 1, M, 1,-M, 1, -M, 1, -M, 1, -M, 1, M, 1,
-M, 1, -1, -M, -1, M, -, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 1, -M, 1, M, 1,-M, 1, -M, 1, -M, 1, -M, 1,
M, 1, -M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M, -1, -M, -1, M,
-1, -M, 1, M, 1, -M, 1, -M}, (1+j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M,
-1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M, 1, M, 1,
-M, 1, M, -1, -M, -1, M, -1, M}(1+j)/ {square root over (2)};
or
{-M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M,
1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M, -1, -M, -1,
M, -1, -M, 1, M, 1, -M, 1, -M}(1+j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, -1, M, -1, -M, -1, M, -1, M, -1, M, -1,
M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, --M, -1, -M, 1, -M, 1, M,
1, -M, 0, M, -1, -M, -1, M, -1, M}(1+j)/ {square root over (2)};
or
{-M, 1, -M, 1, M, 1, -M, 1, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M,
1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M, -1, -M, -1,
M, 0, -M, 1,M, 1, -M}(1+j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, -1, M, -1, -M, -1, M, -1, M, -1, M, -1,
M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1,
-M, 1, M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 1, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M,
1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M, -1,
M, -1, -M, 1, M, 1, -M, 1, -M}(1j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, -1, M, -1, -M, -1, M, -1, M, 0, M, -1, M,
-1, -M, -1, m, 0, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M, 1, M, 1,
-M, 1, M, -1, -M, -1, M, -1, M}(1+j)/ {square root over (2)};
or
{-M, 1, -M, 1, M, 1, -M, 1, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M,
1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M, -1, -M, -1,
M, -1, -M, 1, M, 1, -M, 1, -M}(1+j)/ {square root over (2)}.
As described above, the short training sequence corresponding to
the 240-MHz
EHT-STF may be expressed as S.sub.-1528:8:1528. Therefore, the
values given by the foregoing short training sequence each
correspond to a frequency-domain sequence value that starts with a
tone whose subscript is -1528 and ends with a tone whose subscript
is 1528, with a spacing of 8 tones in between.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 1.6 .mu.s and
the channel bandwidth of 240 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that, by using the method 2,
the short training sequence corresponding to the 240-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained through
transformation based on the M-sequence.
Method 3
The short training sequence corresponding to the EHT-STF in the
foregoing method 1 or method 2 is directly cached or stored
locally. When the short training sequence corresponding to the
EHT-STF is to be used, the short training sequence corresponding to
the EHT-STF is directly obtained locally.
It should be understood that the foregoing three methods are merely
examples for description, and this application is not limited
thereto. Any method that can be used to obtain the short training
sequence corresponding to the 240-MHz EHT-STF with the periodicity
of 1.6 .mu.s falls within the protection scope of this embodiment
of this application.
Similar to that in the scenario 1, the short training sequence
corresponding to the 240-MHz EHT-STF with the periodicity of 1.6
.mu.s may be obtained through simulation calculation. For example,
if the method 1 is used, the short training sequence corresponding
to the 240-MHz EHT-STF with the periodicity of 1.6 .mu.s may be
obtained through calculation based on a stored short training
sequence that corresponds to an HE-STF and by using a corresponding
formula. For another example, if the method 2 is used, the short
training sequence corresponding to the 240-MHz EHT-STF with the
periodicity of 1.6 .mu.s may be obtained through calculation based
on a stored or protocol-specified M-sequence by using a
corresponding formula.
Specifically, the foregoing 10 sequences may be alternatively
designed based on a frequency-domain sequence HES.sub.-504:8:504
defined in 802.11ax for an 80-MHz HE-STF with a periodicity of 1.6
.mu.s. A detailed design formula is as follows:
S.sub.-1528:8:1528={c.sub.1L2, a.sub.1, c.sub.2R2, a.sub.2,
c.sub.3L2, 0, c.sub.4R2, a.sub.3, c.sub.5L2, s.sub.4,
c.sub.6R2}(1+j)/ {square root over (2)} (4)
where
L2=HES.sub.-504:8:-8 {square root over (2)}/(1+j)={M, -1, M, -1,
-M, -1, M};
R2=HES.sub.8:8:504 {square root over (2)}/(1+j)={-M, 1, M, 1, -M,
1, -M}
S.sub..+-.15280; and
similarly,
a value of a.sub.i is {-1, 0, 1}, and i=1, 2, 3, 4; and
a value of c.sub.j is {-1, 1}, and j=1, 2, 3, 4, 5, 6.
Similarly, when the short training sequence corresponding to the
240-MHz EHT-STF with the periodicity of 1.6 .mu.s is obtained by
using the method 1, the short training sequence may be obtained
based on the stored HES.sub.-504:8:-8 and HES.sub.8:8:504 by using
the formula (4). Alternatively, when the short training sequence
corresponding to the 240-MHz EHT-STF with the periodicity of 1.6
.mu.s is obtained by using the method 2, the short training
sequence may be obtained based on the M-sequence by using the
formula (4).
The short training sequence corresponding to the 240-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained based on the
formula (4). In addition, simulation calculation is performed, for
example, a.sub.i and c.sub.i are adjusted, so that a PAPR
corresponding to the short training sequence corresponding to the
EHT-STF is less than or equal to a preset second threshold, to
obtain a sequence with comparatively good performance.
Specifically, after 2.sup.6.times.3.sup.4=5184 exhaustive searches
are performed, all possible S.sub.-1528:8:1528 and corresponding
PAPR values may be obtained, and S.sub.-1528:8:1528 with a smallest
PAPR is finally obtained through comparison. Table 3 shows a.sub.i
and c.sub.i in 10 groups of optimal S when the short training
sequence of the 240-MHz EHT-STF with the periodicity of 1.6 .mu.s
is designed based on the short training sequence corresponding to
the 80 -MHz and 1.6 .mu.s HE-STF.
Setting a preset threshold (for example, the preset second
threshold) may be performing exhaustion on the parameter set A and
the parameter set C, and performing setting based on a minimum PAPR
value (for example, 10 groups of results with minimum PAPRs in
Table 3) obtained in an exhaustion process, or may be performing
setting comprehensively with reference to a minimum PAPR value
obtained in an exhaustion result, a property of a sequence, and the
like, or may be performing setting comprehensively with reference
to a minimum PAPR value obtained in an exhaustion result, a preset
parameter, and the like; or the preset threshold may be specified
in advance; or the preset threshold may be obtained based on a
plurality of experiment results, or the like.
TABLE-US-00003 TABLE 3 Values of parameter sets for the short
training sequence S corresponding to the 240-MHz EHT-STF with the
periodicity of 1.6 .mu.s Sequence number a.sub.1 a.sub.2 a.sub.3
a.sub.4 c.sub.1 c.sub.2 c.sub.3 c.sub.4 c.s- ub.5 c.sub.6 PAPR (dB)
1 -1 -1 1 1 1 -1 1 1 -1 -1 6.6498 2 1 1 -1 -1 -1 1 -1 -1 1 1 6.6498
3 0 -1 1 1 1 -1 1 1 -1 -1 6.6997 4 0 1 -1 -1 -1 1 -1 -1 1 1 6.6997
5 -1 -1 1 0 1 -1 1 1 -1 -1 6.7272 6 1 1 -1 0 -1 1 -1 -1 1 1 6.7272
7 -1 -1 0 1 1 -1 1 1 -1 -1 6.7826 8 1 1 0 -1 -1 1 -1 -1 1 1 6.7826
9 -1 0 1 1 1 -1 1 1 -1 -1 6.7929 10 1 0 -1 -1 -1 1 -1 -1 1 1
6.7929
The values of a.sub.i and c.sub.1 in the obtained 10 groups of
results are separately substituted into the formula (4), and it can
be learned that the short training sequence corresponding to the
240-MHz EHT-STF with the periodicity of 1.6 .mu.s may be expressed
as follows:
{L2, -1, -R2, -1, L2, 0, R2, 1, -L2, 1, -R2}(1+j)/ {square root
over (2)}; or
{-L2, 1, R2, 1, -L2, 0, -R2, -1, L2, -1, R2}(1+j)/ {square root
over (2)}; or
{L2, 0, -R2, -1, L2, 0, R2, 1, -L2, 1, -R2}(1+j)/ {square root over
(2)}; or
{-L2, 0, R2, 1, -L2, 0, -R2, -1, L2, -1, R2}(1+j)/ {square root
over (2)}; or
{L2, -1, -R2, -1, L2, 0, R2, 1, -L2, 0, -R2}(1+j)/ {square root
over (2)}; or
{-L2, 1, R2, 1, -L2, 0, -R2, -1, L2, 0, R2}(1+j)/ {square root over
(2)}; or
{L2, -1, -R2, -1, L2, 0, R2, 0, -L2, 1, -R2}(1+j)/ {square root
over (2)}; or
{-L2, 1, R2, 1, -L2, 0, -R2, 0, L2, -1, R2}(1+j)/ {square root over
(2)}; or
{L2, -1, -R2, 0, L2, 0, R2, 1, -L2, 1, -R2}(1+j)/ {square root over
(2)}; or
{-L2, 1, R2, 0, -L2, 0, -R2, -1, L2, -1, R2}(1+j)/ {square root
over (2)}.
L2 expressed as {M, -1, M, -1, -M, -1, M}, R2 expressed as {-M, 1,
M, 1, -M, 1, -M}, -L2={-M, 1, -M, 1, M, 1, -M}, and -R2 expressed
as {M, -1, -M, -1, M, -1, M} may be substituted to obtain the short
training sequence corresponding to the 240-MHz EHT-STF with the
periodicity of 1.6 .mu.s.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 1.6 .mu.s and
the channel bandwidth of 240 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that L2 and R2 are sequences
related to the 80 -MHz and 1.6-.mu.s short training sequence.
Therefore, the 240-MHz short training sequence can be compatible
with the 80-MHz short training sequence. In addition, the 240-MHz
short training sequence can support automatic gain control on a
high-bandwidth (the bandwidth is greater than 160 MHz) channel. In
addition, it is verified through simulation and comparison between
the PAPRs in Table 3 and the PAPRs in 802.11ax (Table 1) that these
short training sequences have comparatively small peak-to-average
power ratios, and therefore can support automatic gain control on a
high-bandwidth channel and can improve an estimation effect for an
automatic gain control circuit at a receive end, thereby reducing a
receive bit error rate. Therefore, the short training sequence
proposed for a high channel bandwidth in this solution of this
application can control a PAPR to be very small.
Example 2: The bandwidth of the target channel is 320 MHz.
The following describes a short training sequence S corresponding
to a 320-MHz EHT-STF still by using a scenario in which the
periodicity is 0.8 .mu.s and a scenario in which the periodicity is
1.6 .mu.s
Scenario 1: The periodicity is 0.8 .mu.s.
When the periodicity is 0.8 .mu.s and the bandwidth of the target
channel is 320 MHz, different 320-MHz EHT-STFs are obtained based
on HE-STFs for reference channels with different bandwidths. The
following describes different expressions of the 320-MHz EHT-STF
with reference to a manner A and a manner B.
Manner A
Obtain, based on a short training sequence corresponding to an
80-MHz HE-STF with a periodicity of 0.8 .mu.s, a short training
sequence S corresponding to a 320-MHz EHT-STF with a periodicity of
0.8 .mu.s.
The 320-MHz bandwidth has 1024.times.4=4096 tones in total. There
are 12 guard tones on a left edge, 11 guard tones on a right edge,
and 11+12=23 direct-current tones in the middle of the bandwidth.
When the periodicity included in the short training field is 0.8
.mu.s, the short training sequence may be expressed as
S.sub.-2032:16:2032, where -2032 indicates a subscript of a
starting tone, 2032 indicates a subscript of an ending tone, 16
indicates a spacing, and -2032:16:2032 indicates starting with a
tone whose subscript is -2032 and ending with a tone whose
subscript is 2032, with a spacing of 16 tones in between. On other
tones, a frequency-domain sequence value is 0.
Similarly, in this embodiment of this application, the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 0.8 .mu.s may be determined by using at least the
following three methods.
Method 1
Determine, based on a frequency-domain sequence HES for a reference
channel, the short training sequence S corresponding to the 320-MHz
EHT-STF with the periodicity of 0.8 .mu.s.
Optionally, the short training sequence S corresponding to the
EHT-STF with the periodicity of 0.8 .mu.s and the target channel
bandwidth of 320 MHz may be expressed as follows:
{L1, 0, -R1, 0, L1, 0, R1, 0, L1, 0, -R1, -1, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 0, -L1, 0, -R1, 0, -L1, 0, R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, -1, L1, 0, R1, 0, L1, 0, -R1, -1, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 1, -L1, 0, -R1, 0, -L1, 0, R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 0, -L1, 0, R1, 0, -L1, 0, -R1, -1, -L1, 0, -R1}(1+j(/
{square root over (2)}; or
{-L1, 0, R1, 0, L1, 0, -R1, 0, L1, 0, R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 0, L1, 0, -R1, 0, -L1, 0, -R1, 0, L1, 0, R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 0, -L1, 0, R1, 0, L1, 0, R1, 0, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 1, L1, 0, -R1, 0, -L1, 0, -R1, -1, L1, 0, -R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, -1, -L1, 0, R1, 0, L1, 0, R1, 1, -L1, 0, -R1}(1+j)/
{square root over (2)}, where similarly,
L1=HES.sub.Left 1 {square root over (2)}/(1+j)=HES.sub.-496:16:-16
{square root over (2)}/(1+j), and R1=HES.sub.Right 1 {square root
over (2)}/(1+j)=HES.sub.16:16:496 {square root over (2)}/(1+j):
HES.sub.-496:16:496 is an HES corresponding to 80 MHz and the
periodicity of 0.8 .mu.s; and
L1 is expressed as {M, 1, -M}, R1 is expressed as {-M, 1, -M}, -L1
is expressed as {-M, -1, M}, and -R1 is expressed as {M, -1,
M}.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -2032 and ends with a tone
whose subscript is 2032, with a spacing of 16 tones in between.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 0.8 .mu.s and
the channel bandwidth of 320 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that, by using the method 1,
the short training sequence S corresponding to the 320-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained through
transformation based on an HES specified in a standard.
Method 2
Obtain, through transformation based on an M-sequence, the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 0.8 .mu.s.
Specifically, L1 expressed as {M, 1, -M}, R1 expressed as {-M, 1,
-M}, -L1 expressed as {-M, -1, M}, and -R1 expressed as {M, -1, M}
are substituted, and it can be learned that the short training
sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 0.8 .mu.s may be expressed as follows:
{M, 1, -M, 0, M, -1, M, 0, M, 1, -M, 0, -M, 1, -M, 0, M, 1, -M, 0,
M, -1, M, -1, -M, -1, M, 0, M, -1, M}(1+j)/ {square root over (2)};
or
{-M, -1, M, 0, -M, 1, -M, 0, -M, -1, M, 0, M, -1, M 0, -M, -1, M 0,
-M, 1, -M, 1M, 1, -M, 0, -M, 1, -M}(1+j)/ {square root over (2)};
or
{M, 1, -M, 0, M, -1, M, -1, M, 1, -M, 0, -M, 1, -M, 0, M, 1, -M, 0,
M, -1, M, -1, -M, -1, M, 0, M, -1, , M}(1+j)/ {square root over
(2)}; or
{-M, -1, M, 0, -M, 1, -M, -1, -M, -1, M, 0, M, -1, M, 0, -M, -1, M,
0, -M, 1, -M, 1, M, 1, -M, 0, -M, 1, -M}(1+j)/ {square root over
(2)}; or
{M, 1, -M, 0, M, -1, M, 0, -M, -1, M, 0, -M, 1, -M, 0, -M, -1, M,
0, M, -1, M, -1, -M, -1, M, 0, M, -1, M}(1+j)/ {square root over
(2)}; or
{-M, -1, M, 0, -M, 1, -M, 0, M, 1, -M, 0, M, -1, M, 0, M, 1, -M, 0,
-M, 1, -M, 1, M, 1, -M, 0, -M, 1, -M}(1+j)/ {square root over (2)};
or
{M, 1, -M, 0, M, -1, M, 0, M, 1, -M, 0, M, -1, M, 0, -M, -1, M, 0,
M, -1, M, 0, M, 1, -M, 0, -M, 1, -M}(1+j)/ {square root over (2)};
or
{-M, -1, M, 0, -M, 1, -M, 0, -M, -1, M, 0, -M, 1, -M, 0, M, 1, -M,
0, -M, 1, -M, 0, -M, -1, M, 0, M, -1, M}(1+j)/ {square root over
(2)}; or
{M, 1, -M, 0, M, -1, M, 1, M, 1, -M, 0, M, -1, M, 0, -M, -1, M, 0,
M, -1, M, -1, M, 1, -M, 0, -M, 1, -M}(1+j)/ {square root over (2)};
or
{-M, -1, M, 0, -M, 1, -M, -1, -M, -1, M, 0, -M, 1, -M, 0, M, 1, -M,
0, -M, 1, -M, 1, -M, -1, M, 0, M, -1, M}(1+j)/ {square root over
(2)}.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -2032 and ends with a tone
whose subscript is 2032, with a spacing of 16 tones in between.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 0.8 .mu.s and
the channel bandwidth of 320 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that, by using the method 2,
the short training sequence S corresponding to the 320-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained through
transformation based on the M-sequence.
Method 3
The short training sequence corresponding to the EHT-STF in the
foregoing method 1 or method 2 is directly cached or stored
locally. When the short training sequence corresponding to the
EHT-STF is to be used, the short training sequence corresponding to
the EHT-STF is directly obtained locally.
It should be understood that the foregoing three methods are merely
examples for description, and this application is not limited
thereto. Any method that can be used to obtain the short training
sequence corresponding to the 320-MHz EHT-STF with the periodicity
of 0.8 us falls within the protection scope of this embodiment of
this application.
The short training sequence corresponding to the 320-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained through
simulation calculation. For example, if the method 1 is used, the
short training sequence corresponding to the 320-MHz EHT-STF with
the periodicity of 0.8 .mu.s may be obtained through calculation
based on a stored frequency-domain sequence HES that corresponds to
an HE-STF and by using a corresponding formula. For another
example, if the method 2 is used, the short training sequence
corresponding to the 320-MHz EHT-STF with the periodicity of 0.8
.mu.s may be obtained through calculation based on a stored or
protocol-specified M-sequence by using a corresponding formula.
Specifically, similar to the design of the EHT-STF for the channel
bandwidth of 240 MHz, in this solution of this application, for the
channel bandwidth of 320 MHz, the EHT-STF for a channel with a
bandwidth of 320 MHz is designed based on the HE-STF for a channel
with a bandwidth of 80 MHz. First, a tone plan for the bandwidth of
320 MHz is obtained by combining four tone plans with a bandwidth
of 80 MHz each. Similar to 240 MHz, guard tones on the left and
right and direct-current tones in the middle of each 80 MHz are
reserved. In this way, the 320-MHz bandwidth has 1024.times.4=4096
tones in total, and there are 12 guard tones on a left edge, 11
guard tones on a right edge, and 11+12=23 direct-current tones in
the middle of the bandwidth.
Based on the frequency-domain sequence HES.sub.-496:16:496 defined
in 802.11ax for the 80-MHz HE-STF with the periodicity of 0.8
.mu.s, a detailed design formula for the short training sequence S
corresponding to the 320-MHz EHT-STF with the periodicity of 0.8
.mu.s is as follows: S.sub.-2032:16:203232 {c.sub.1L1, 0, c.sub.2,
R1, a.sub.1, c.sub.3L1, 0, c.sub.4R1, 0, c.sub.5L1, 0, c.sub.6R1,
a.sub.2, c.sub.7L1, 0, c.sub.8R1}(1+j)/ {square root over (2)}
(5)
where
L1=HES.sub.-496:16:-16 {square root over (2)}/(1+j)={M, 1, -M};
R1=HES.sub.16:16:496 {square root over (2)}/(1+j)={-M, 1, -M};
and
similarly,
a value of a.sub.i is {-1, 0, 1}, and i=1, 2; and
a value of c.sub.j is {-1, 1}, and j=1, 2, 3, 4, 5, 6, 7, 8.
Therefore, when the short training sequence corresponding to the
320-MHz EHT-STF with the periodicity of 0.8 .mu.s is obtained by
using the method 1, the short training sequence may be obtained
based on the stored HES.sub.-496:16:-16 and HES16:16:496 by using
the formula (5). Alternatively, when the short training sequence
corresponding to the 320-MHz EHT-STF with the periodicity of 0.8
.mu.s is obtained by using the method 2, the short training
sequence may be obtained based on the M-sequence by using the
formula (5).
The short training sequence corresponding to the 320-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained based on the
formula (5). In addition, simulation calculation is performed, for
example, a, and c, are adjusted, so that a PAPR corresponding to
the short training sequence corresponding to the EHT-STF is less
than or equal to a preset third threshold, to obtain a sequence
with comparatively good performance.
Specifically, after 2.sup.8.times.3.sup.2=2304 exhaustive searches
are performed, all possible S.sub.-2032:16:2032 and corresponding
PAPR values may be obtained, and S.sub.-2032:16:2032 with a
smallest PAPR is finally obtained through comparison. Table 4 shows
a.sub.i and c.sub.i in 10 groups of optimal S when the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 0.8 .mu.s is designed based on the frequency-domain
sequence HES of the 80-MHz HE-STF with the periodicity of 0.8
.mu.s.
Setting a preset threshold (for example, the preset third
threshold) may be performing exhaustion on the parameter set A and
the parameter set C, and performing setting based on a minimum PAPR
value (for example, 10 groups of results with minimum PAPRs in
Table 4) obtained in an exhaustion process, or may be performing
setting comprehensively with reference to a minimum PAPR value
obtained in an exhaustion result, a property of a sequence, and the
like, or may be performing setting comprehensively with reference
to a minimum PAPR value obtained in an exhaustion result, a preset
parameter, and the like; or the preset threshold may be specified
in advance; or the preset threshold may be obtained based on a
plurality of experiment results, or the like.
TABLE-US-00004 TABLE 4 Values of parameter sets for the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 0.8 .mu.s Sequence number a.sub.1 a.sub.2 a.sub.3
a.sub.4 c.sub.1 c.sub.2 c.sub.3 c.sub.4 c.s- ub.5 c.sub.6 PAPR (dB)
1 0 -1 1 -1 1 1 1 -1 -1 -1 4.7164 2 0 1 -1 1 -1 -1 -1 1 1 1 4.7164
3 -1 -1 1 -1 1 1 1 -1 -1 -1 4.7482 4 1 1 -1 1 -1 -1 -1 1 1 1 4.7482
5 0 -1 1 -1 -1 1 -1 -1 -1 -1 4.8001 6 0 1 -1 1 1 -1 1 1 1 1 4.8001
7 0 0 1 -1 1 -1 -1 -1 1 1 4.8576 8 0 0 -1 1 -1 1 1 1 -1 -1 4.8576 9
1 -1 1 -1 1 -1 -1 -1 1 1 4.8615 10 -1 1 -1 1 -1 1 1 1 -1 -1
4.8615
The values of a.sub.i and c.sub.i in the obtained 10 groups of
results are separately substituted into the formula (5) , and it
can be learned that the short training sequence corresponding to
the 320-MHz EHT-STF with the periodicity of 0.8 .mu.s may be
expressed as follows:
{L1, 0, -R1, 0, L1, 0, R1, 0, L1, 0, -R1, -1, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 0, -L1, 0, -R1, 0, -L1, 0, R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, -1, L1, 0, R1, 0, L1, 0, -R1, -1, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 1, -L1, 0, -R1, 0, -L1, 0, R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 0, -L1, 0, R1, 0, -L1, 0, -R1, -1, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 0, L1, 0, -R1, 0, L1, 0, R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 0, L1, 0, -R1, 0, -L1, 0, -R1, 0, L1, 0, R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, 0, -L1, 0, R1, 0, L1, 0, R1, 0, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
{L1, 0, -R1, 1, L1, 0, -R1, 0, -L1, 0, -R1, 1, L1, 0, R1}(1+j)/
{square root over (2)}; or
{-L1, 0, R1, -1, -L1, 0, R1, 0, L1, 0, R1, 1, -L1, 0, -R1}(1+j)/
{square root over (2)}; or
L1 expressed as {M, 1, -M}, expressed as {M, 1, -M}, -L1 expressed
as {M, -1, M}, and -R1 expressed as {M, -1, M} may be substituted
to obtain the short training sequence corresponding to the 320-MHz
EHT-STF with the periodicity of 0.8 .mu.s.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 0.8 .mu.s and
the channel bandwidth of 320 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that L1 and R1 are sequences
related to the short training sequence corresponding to 80 MHz and
the periodicity of 0.8 .mu.s. Therefore, the 320-MHz short training
sequence can be compatible with the 80-MHz short training sequence.
In addition, the 320-MHz short training sequence can support
automatic gain control on a high-bandwidth (the bandwidth is
greater than 160 MHz) channel. In addition, it is verified through
simulation and comparison between the PAPRs in Table 4 and the
PAPRs in 802.11ax (Table 1) that these short training sequences
have comparatively small peak-to-average power ratios, and
therefore can support automatic gain control on a high-bandwidth
channel and can improve an estimation effect for an automatic gain
control circuit at a receive end, thereby reducing a receive bit
error rate. Therefore, the short training sequence proposed for a
high channel bandwidth in this solution of this application can
control a PAPR to be very small.
Manner B
Obtain, based on a 160-MHz frequency-domain sequence HES with a
periodicity of 0.8 .mu.s, a short training sequence S corresponding
to a 320-MHz EHT-STF with a periodicity of 0.8 .mu.s.
The 320-MHz bandwidth has 2048.times.2=4096 tones in total. When
the periodicity included in the short training field is 0.8 .mu.s,
the short training sequence may be expressed as
S.sub.-2032:16:2032, where -2032 indicates a subscript of a
starting tone, 2032 indicates a subscript of an ending tone, 16
indicates a spacing, and -2032:16:2032 indicates starting with a
tone whose subscript is 2032 and ending with a tone whose subscript
is 2032, with a spacing of 16 tones in between. On other tones, a
frequency-domain sequence value is 0.
Similarly, in this embodiment of this application, the short
training sequence corresponding to the 302-MHz EHT-STF with the
periodicity of 0.8 .mu.s may be determined by using at least the
following three methods.
Method 1
Determine, based on a frequency-domain sequence HES for a bandwidth
of a reference channel, the short training sequence S corresponding
to the 320-MHz EHT-STF with the periodicity of 0.8 .mu.s.
Optionally, the short training sequence corresponding to the
EHT-STF with the periodicity of 0.8 .mu.s and the target channel
bandwidth of 320 MHz may be expressed as follows:
{L3, 0, R3, 0, -L3, -1, R3}(1+j)/ {square root over (2)}; or
{-L3, 0, -R3, 0, L3, 1, -R3}(1+j)/ {square root over (2)}; or
{L3, 0, R3, 0, -L3, 0, R3}(1+j)/ {square root over (2)}; or
{-L3, 0, -R3, 0, L3, 0, -R3}(1+j)/ {square root over (2)}; or
{L3, 1, R3, 0, -L3, 1, -R3}(1+j)/ {square root over (2)}; or
{-L3, -1, R3, 0, L3, -1, R3}(1+j)/ {square root over (2)}; or
{L3, 1, -R3, 0, -L3, 0, -R3}(1+j)/ {square root over (2)}; or
{-L3, -1, R3, 0, L3, 0, R3}(1+j)/ {square root over (2)}; or
{L3, 1, R3, 0, -L3, -1, R3}(1+j)/ {square root over (2)}; or
{-L3, -1, -R3, 0, L3, 1, -R3}(1+j)/ {square root over (2)}, where
similary,
L3=HES.sub.-1008:16:-16 {square root over (2)}/(1+j)={M, 1, -M, 0,
-M, 1, -M}, and HES.sub.-1008:16:-16 is a part of
HES.sub.-1008:16:1008 on the left of a tone 0;
R3=HES.sub.16:16:1008 {square root over (2)}/(1+1)={-M, -1, M, 0,
-M, 1, -M}, and HES.sub.16:16:1008 is a part of
HES.sub.-1008:16:1008 on the right of the tone 0; and
HES.sub.-1008:16:1008 is an HES corresponding to 160 MHz and the
periodicity of 0.8 .mu.s.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -2032 and ends with a tone
whose subscript is 2032, with a spacing of 16 tones in between.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 0.8 .mu.s and
the channel bandwidth of 320 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that, by using the method 1,
the short training sequence corresponding to the 320-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained through
transformation based on an HES specified in a standard.
Method 2
Obtain, through transformation based on an M-sequence, the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 0.8 .mu.s.
Specifically, L3 expressed as {M, 1, -M, 0, -M, 1, -M}, R3
expressed as {-M, -1, M, 0, -M, 1, -M}, -L3 expressed as {-M, -1,
M, 0, M, -1, M}, and -R3 expressed as {M, 1, -M, 0, M, -1, M} are
substituted, and it can be learned that the short training sequence
corresponding to the 320-MHz EHT-STF with the periodicity of 0.8
.mu.s may be expressed as follows:
{M, 1, -M, 0, -M, 1, -M, 0, -M, -1, M, 0, -M, 1, -M, 0, -M, -1, M,
0, M, -1, M, -1, -M, -1, M, 0, -M, 1, -M}(1+j)/ {square root over
(2)}; or
{-M, -1, M, 0, M, -1, M, 0, M, 1, -M, 0, M, -1, M, 0, M, 1, -M, 0,
-M, 1, -M, 1, M, 1, -M, 0, M, -1, M}(1+j)/ {square root over (2)};
or
{M, 1, -M, 0, -M, 1, -M, 0, -M, -1, M, 0, -M, 1, -M, 0, -M, -1, M,
0, M, -1, M, 0, -M, -1, M, 0, -M, 1, -M}(1+j)/ {square root over
(2)}; or
{M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M, 0, M, -1, M, 0, -M, -1, M, 0,
M, -1, M, 1, M, 1, -M, 0, M, -1, M}(1+j)/ {square root over (2)};
or
{M, 1, -M, o, -M, 1, -M, 1, M, 1, -M, 0, M, -1, M, 0, -M, -1, M, 0,
M, -1, M, 1, M, 1, -M, 0, M, -1, M, }(1+j) {square root over (2)};
or
{-M, -1, M, 0, M, -1, M, -1, -M, -1, M, 0, -M, 1, -M, 0, M, 1, -M,
0, M, -1, -M, -1, -M, -1, M, 0, -M, 1, -M}(1+j)/ {square root over
(2)}; or
{M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M, 0, M, -1, M, 0, -M, -1, M, 0,
M, -1, M, 0, M, 1, -M, 0, M, -1, M, }(1+j) {square root over (2)};
or
{-M, -1, M, 0, M, -1, M, -1, -M, -1, M, 0, -M, 1, -M, 0, M, 1, -M,
0, M, -1, -M, 0, -M, -1, M, 0, -M, 1, -M}(1+j)/ {square root over
(2)}; or
{M, 1, -M, 0, -M, 1, -M, 1, -M, -1, M, 0, -M, 1, -M, 0, -M, -1, M,
0, M, -1, M, -1, M, -, M, 0, -M, 1, -M}(1+j)/ {square root over
(2)}; or
{-M, -1, M, 0, M, -1, M, -1, M, 1, -M, 0, M, -1, M, 0, M, 1, -M, 0,
-M, 1, -M, 1, M, 1, -M, 0, M, -1, M}(1+j)/ {square root over
(2)}.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -2032 and ends with a tone
whose subscript is 2032, with a spacing of 16 tones in between.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 0.8 .mu.s and
the channel bandwidth of 320 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that, by using the method 2,
the short training sequence S corresponding to the 320-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained through
transformation based on the M-sequence.
Method 3
The short training sequence corresponding to the EHT-STF in the
foregoing method 1 or method 2 is directly cached or stored
locally. When the short training sequence corresponding to the
EHT-STF is to be used, the short training sequence corresponding to
the EHT-STF is directly obtained locally.
It should be understood that the foregoing three methods are merely
examples for description, and this application is not limited
thereto. Any method that can be used to obtain the short training
sequence corresponding to the 320-MHz EHT-STF with the periodicity
of 0.8 .mu.s falls within the protection scope of this embodiment
of this application.
Similar to that in the scenario 1, the short training sequence S
corresponding to the 320-MHz EHT-STF with the periodicity of 0.8
.mu.s may be obtained through simulation calculation. For example,
if the method 1 is used, the short training sequence S
corresponding to the 320-MHz EHT-STF with the periodicity of 0.8
.mu.s may be obtained through calculation based on a stored
frequency-domain sequence HES that corresponds to an HE-STF and by
using a corresponding formula. For another example, if the method 2
is used, the short training sequence S corresponding to the 320-MHz
EHT-STF with the periodicity of 0.8 .mu.s may be obtained through
calculation based on a stored or protocol-specified M-sequence by
using a corresponding formula.
Specifically, the EHT-STF with the bandwidth of 320 MHz may be
alternatively constructed by rotating and combining HE-STFs with a
bandwidth of 160 MHz. Specifically, the short training sequence S
corresponding to the 320-MHz EHT-STF with the periodicity of 0.8
.mu.s may be designed based on the frequency-domain sequence
HES.sub.-1008:16:1008 defined in 802.11ax for the 160-MHz HE-STF
with the periodicity of 0.8 .mu.s. A detailed design formula
thereof is as follows: S.sub.-2032:16:20={c.sub.1L3, a.sub.1,
c.sub.2R3, 0, c.sub.3L3, a.sub.2, c.sub.4R3}(1+j)/ {square root
over (2)} (6)
where
L3=HES.sub.-1008:16:-16 {square root over (2)}/(1+j)={M, 1, -M, 0,
-M, 1, -M};
R3=HES.sub.16:16:1008 {square root over (2)}/(1+j)={-M, -1, M, 0,
-M, 1, -M}; and
similarly,
a value of a.sub.i is {-1, 0, 1}, and i=1, 2; and
a value of c.sub.j is {-1, 1, }, and j=1, 2, 3, 4.
Similarly, when the short training sequence corresponding to the
320-MHz EHT-STF with the periodicity of 0.8 .mu.s is obtained by
using the method 1, the short training sequence may be obtained
based on the stored HES.sub.-1008:16:-16 and HES.sub.16:16:1008 by
using the formula (6). Alternatively, when the short training
sequence corresponding to the 320-MHz EHT-STF with the periodicity
of 0.8 .mu.s is obtained by using the method 2, the short training
sequence may be obtained based on the M-sequence by using the
formula (6).
The short training sequence corresponding to the 320-MHz EHT-STF
with the periodicity of 0.8 .mu.s may be obtained based on the
formula (6). In addition, simulation calculation is performed, for
example, a, and c, are adjusted, so that a PAPR corresponding to
the short training sequence corresponding to the EHT-STF is less
than or equal to a preset fourth threshold, to obtain a sequence
with comparatively good performance.
Specifically, after 2.sup.4.times.3.sup.2=144 exhaustive searches
are performed, all possible S.sub.-2032:16:2032 and corresponding
PAPR values may be obtained, and S.sub.-2032:16:2032 with a
smallest PAPR is finally obtained through comparison. Table 5 shows
a.sub.i and c.sub.i in 10 groups of optimal S when the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 0.8 .mu.s is designed based on the 160-MHz HE-STF
with the periodicity of 0.8 .mu.s.
Setting a preset threshold (for example, the preset fourth
threshold) may be performing exhaustion on the parameter set A and
the parameter set C, and performing setting based on a minimum PAPR
value (for example, 10 groups of results with minimum PAPRs in
Table 5) obtained in an exhaustion process, or may be performing
setting comprehensively with reference to a minimum PAPR value
obtained in an exhaustion result, a property of a sequence, and the
like, or may be performing setting comprehensively with reference
to a minimum PAPR value obtained in an exhaustion result, a preset
parameter, and the like; or the preset threshold may be specified
in advance; or the preset threshold may be obtained based on a
plurality of experiment results, or the like.
TABLE-US-00005 TABLE 5 Values of parameter sets for the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 0.8 .mu.s Sequence PAPR number a.sub.1 a.sub.2
c.sub.1 c.sub.2 c.sub.3 c.sub.4 (dB) 1 0 -1 1 1 -1 1 5.2021 2 0 1
-1 -1 1 -1 5.2021 3 0 0 1 1 -1 1 5.2404 4 0 0 -1 -1 1 -1 5.2404 5 1
1 1 -1 -1 -1 5.2691 6 -1 -1 -1 1 1 1 5.2691 7 1 0 1 -1 -1 -1 5.3267
8 -1 0 -1 1 1 1 5.3267 9 1 -1 1 1 -1 1 5.3441 10 -1 1 -1 -1 1 -1
5.3441
The values of a, and c, in the obtained 10 groups of results are
separately substituted into the formula (6), and it can be learned
that the short training sequence S corresponding to the 320-MHz
EHT-STF with the periodicity of 0.8 .mu.s may be expressed as
follows:
{L3, 0, R3, 0, -L3, -1, R3}(1+j)/ {square root over (2)}; or
{-L3, 0, -R3, 0, L3, 1, -R3}(1+j)/ {square root over (2)}; or
{L3, 0, R3, 0, -L3, 1, R3}(1+j)/ {square root over (2)}; or
{-L3, 0, -R3, 0, L3, 0, -R3}(1+j)/ {square root over (2)}; or
{L3, 1, -R3, 0, -L3, 1, -R3}(1+j)/ {square root over (2)}; or
{-L3, -1, R3, 0, L3, -1, R3}(1+j)/ {square root over (2)}; or
{L3, 1, -R3, 0, -L3, 0, -R3}(1+j)/ {square root over (2)}; or
{-L3, -1, R3, 0, L3, 0, R3}(1+j)/ {square root over (2)}; or
{L3, 1, R3, 0, -L3, -1, R3}(1+j)/ {square root over (2)}; or
{-L3, -1, -R3, 0, L3, 1, -R3}(1+j)/ {square root over (2)}.
L3 expressed as {M, 1, -M, o, -M, 1, -M}, R3 expressed as {-M, -1,
M, 0, -M, 1, -M}, -L3 expressed as {-M, -1, M, 0, M, -1, M}, and
-R3 expressed as {M, 1, -M, 0, M, -1, M} may be substituted to
obtain the short training sequence S corresponding to the 320-MHz
EHT-STF with the periodicity of 0.8 .mu.s.
It should be understood that the short training sequence S
corresponding to the EHT-STF with the periodicity of 0.8 .mu.s and
the channel bandwidth of 320 MHz may be expressed as any one of the
foregoing 10 expressions.
It should be noted that the foregoing manner A and manner B are
merely examples for description, and this embodiment of this
application is not limited thereto.
It can be learned from the foregoing that L3 and R3 are sequences
related to the short training sequence corresponding to 160 MHz and
the periodicity of 0.8 .mu.s. Therefore, the 320-MHz short training
sequence can be compatible with the 160-MHz short training
sequence. In addition, the 320-MHz short training sequence can
support automatic gain control on a high-bandwidth (the bandwidth
is greater than 160 MHz) channel. In addition, it is verified
through simulation and comparison between the PAPRs in Table 5 and
the PAPRs in 802.11ax (Table 1) that these short training sequences
have comparatively small peak-to-average power ratios, and
therefore can support automatic gain control on a high-bandwidth
channel and can improve an estimation effect for an automatic gain
control circuit at a receive end, thereby reducing a receive bit
error rate. Therefore, the short training sequence proposed for a
high channel bandwidth in this solution of this application can
control a PAPR to be very small.
Scenario 2: The periodicity is 1.6 .mu.s.
Similarly, when the periodicity is 1.6 .mu.s and the bandwidth of
the target channel is 320 MHz, different 320-MHz EHT-STFs are
obtained based on HE-STFs for different bandwidths of a reference
channel. The following describes different expressions of the
320-MHz EHT-STF with reference to a manner A and a manner B.
Manner A
Obtain, based on an 80-MHz frequency-domain sequence HES with a
periodicity of 1.6 .mu.s, a short training sequence S corresponding
to a 320-MHz EHT-STF with a periodicity of 1.6 .mu.s.
The 320-MHz bandwidth has 1024.times.4=4096 tones in total. There
are 12 guard tones on a left edge, 11 guard tones on a right edge,
and 11+12=23 direct-current tones in the middle of the bandwidth.
When the periodicity included in the short training field is 1.6
.mu.s, the short training sequence may be expressed as
S.sub.-2024:8:2024, where -2024 indicates a subscript of a starting
tone, 2024 indicates a subscript of an ending tone, 8 indicates a
spacing, and -2024:8:2024 indicates starting with a tone whose
subscript is -2024 and ending with a tone whose subscript is 2024,
with a spacing of 8 tones in between. On other tones, a
frequency-domain sequence value is 0.
Similarly, in this embodiment of this application, the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s may be determined by using at least the
following three methods.
Method 1
Determine, based on a frequency-domain sequence HES for a bandwidth
of a reference channel, the short training sequence S corresponding
to the 320-MHz EHT-STF with the periodicity of 1.6 .mu.s.
Optionally, the short training sequence S corresponding to the
EHT-STF with the periodicity of 1.6 .mu.s and the target channel
bandwidth of 320 MHz may be expressed as follows:
{L2, 0, -R2, -1, L2, 0, -R2, 0, L2, 0, R2, -1, -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 1, -L2, 0, R2, 0, -L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 0, L2, 0, -R2, 0, L2, 0, R2, -1 -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 0, -L2, 0, R2, 0, -L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, -1, L2, 0, -R2, 0, L2, 0, R2, 0, -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 1, -L2, 0, R2, 0, -L2, 0, -R2, 0, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 1, L2, 0, -R2, 0, L2, 0, R2, -1 -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, -1, -L2, 0, R2, 0, -L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 0, L2, 0, -R2, 0, L2, 0, R2, 0 -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 0, -L2, 0, R2, 0, -L2, 0, -R2, 0, L2, 0, R2}(1+j)/
{square root over (2)}, where similarly,
L2=HES.sub.-504:8:-8 {square root over (2)}/(1+j)={M, -1, M, -1,
-M, -1, M}, and HES.sub.-504:8:-8 is a part of HES.sub.-504:8:504
on the left of a tone 0;
R2=HES.sub.8:8:504 {square root over (2)}/(1+j)={-M, 1, M, 1, -M,
1,-M}, and HES.sub.8:8:504 is a part of HES.sub.-504:8:504 on the
right of the tone 0;
HES.sub.-504:8:504 is an HES corresponding to 80 MHz and the
periodicity of 1.6 .mu.s; and
L2 is expressed as {M, -1, M, -1, -M, -1, M}, R2 is expressed as
{-M, 1, M, 1, -M, 1, -M}, -L2={-M, 1, -M, 1, M, 1, -M}, and -R2 is
expressed as {M, -1, -M, -1, M, -1, M}.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -2024 and ends with a tone
whose subscript is 2024, with a spacing of 8 tones in between.
It should be noted that the short training sequence S corresponding
to the EHT-STF with the periodicity of 1.6 .mu.s and the channel
bandwidth of 320 MHz may be expressed as any one of the foregoing
10 expressions.
It can be learned from the foregoing that, by using the method 1,
the short training sequence corresponding to the 320-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained through
transformation based on an HES specified in a standard.
Method 2
Obtain, through transformation based on an M-sequence, the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s.
Specifically, L2 expressed as {M, -1, M, -1, -M, -1, M}, R2
expressed as {-M, 1, M, 1, -M, 1, -M}, -L2={-M, 1, -M, 1, M, 1,
-M}, and -R2 expressed as {M, -1, -M, -1, M, -1, M} are
substituted, and it can be learned that the short training sequence
corresponding to the 320-MHz EHT-STF with the periodicity of 1.6
.mu.s may be expressed as follows:
{M, -1, M, -1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M,
-1, , -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M,
-1, M, 0, -M, 1, M, 1, -M, 1, -M, -1, -M, 1, -M, 1, M, 1, -M, 0, M,
-1, -M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M,
1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M,
0, M, -1, -M, -1, M, -1, M, 1, M, -1, M, -1, -M, -1, M, 0, -M, 1,
M, 1, -M, 1, -M}(1+J)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M, -1,
M, 0, -M, 1, M, 1, -M, 1, -M, -1, -M, 1, -M, 1, M, 1, -M, 0, M, -1,
-M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M,
1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M,
0, M, -1, -M, -1, M, -1, M, 1, M, -1, M, -1, -M, -1, M, 0, -M, 1,
M, 1, -M, 1, -M}(1+j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M, -1,
M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M, 0, M, -1,
-M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M,
1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M,
0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M, -1, M, 0, -M, 1,
M, 1, -M, 1, -M}(1+J)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 1, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M, -1,
M, 0, -M, 1, M, 1, -M, 1, -M, -1, -M, 1, -M, 1, M, 1, -M, 0, M, -1,
-M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, -1, -M, 1, -M,
1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M,
0, M, -1, -M, -1, M, -1, M, 1, M, -1, M, -1, -M, -1, M, 0, -M, 1,
M, 1, -M, 1, -M}(1+J)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M, -1,
M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M, 0, M, -1,
-M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M,
1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M,
0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M, -1, M, 0, -M, 1,
M, 1, -M, 1, -M}(1+j)/ {square root over (2)}.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -2024 and ends with a tone
whose subscript is 2024, with a spacing of 8 tones in between.
It should be noted that the short training sequence S corresponding
to the EHT-STF with the periodicity of 1.6 .mu.s and the channel
bandwidth of 320 MHz may be expressed as any one of the foregoing
10 expressions.
It can be learned from the foregoing that, by using the method 2,
the short training sequence S corresponding to the 320-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained through
transformation based on the M-sequence.
Method 3
The short training sequence corresponding to the EHT-STF in the
foregoing method 1 or method 2 is directly cached or stored
locally. When the short training sequence corresponding to the
EHT-STF is to be used, the short training sequence corresponding to
the EHT-STF is directly obtained locally.
It should be understood that the foregoing three methods are merely
examples for description, and this application is not limited
thereto. Any method that can be used to obtain the short training
sequence corresponding to the 320-MHz EHT-STF with the periodicity
of 1.6 .mu.s falls within the protection scope of this embodiment
of this application.
The short training sequence S corresponding to the 320-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained through
simulation calculation. For example, if the method 1 is used, the
short training sequence S corresponding to the 320-MHz EHT-STF with
the periodicity of 1.6 .mu.s may be obtained through calculation
based on a stored frequency-domain sequence HES that corresponds to
an HE-STF and by using a corresponding formula. For another
example, if the method 2 is used, the short training sequence S
corresponding to the 320-MHz EHT-STF with the periodicity of 1.6
.mu.s may be obtained through calculation based on a stored or
protocol-specified M-sequence by using a corresponding formula.
Specifically, the foregoing sequences are designed based on the
frequency-domain sequence HES.sub.-504:8:504 defined in 802.11ax
for the 80-MHz HE-STF with the periodicity of 1.6 .mu.s. A detailed
design formula for the short training sequence S corresponding to
the 320-MHz EHT-STF with the periodicity of 1.6 .mu.s is as
follows: S.sub.-2024:8:2024={c.sub.1L2, 0, c.sub.2R2, a.sub.1,
c.sub.3L2, 0, c.sub.4R2, 0, c.sub.5L2, 0, c.sub.6R2, a.sub.2,
c.sub.7L2,0, c.sub.8R2}(1+j) (7)
where
L2=HES.sub.-504:8:8 {square root over (2)}/(1+j)={M, -1, M, -1, -M,
-1, M};
R2=HES.sub.8:8:504 {square root over (2)}/(1+j)={-M, 1, M, 1,
-M};
S.sub..+-.2024=0; and
similarly,
a value of a.sub.i is {-1, 0, 1}, and i=1, 2; and
a value of c.sub.j is {-1, 1}, and j=1, 2, 3, 4, 5, 6, 7, 8.
Therefore, when the short training sequence S corresponding to the
320-MHz EHT-STF with the periodicity of 1.6 .mu.s is obtained by
using the method 1, the short training sequence S may be obtained
based on the stored HES.sub.-504:8:8 and HES.sub.8:8:504 by using
the formula (7). Alternatively, when the short training sequence S
corresponding to the 320-MHz EHT-STF with the periodicity of 1.6
.mu.s is obtained by using the method 2, the short training
sequence S may be obtained based on the M-sequence by using the
formula (7).
The short training sequence corresponding to the 320-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained based on the
formula (7). In addition, simulation calculation is performed, for
example, a.sub.i and c.sub.i are adjusted, so that a PAPR
corresponding to the short training sequence corresponding to the
EHT-STF is less than or equal to a preset fifth threshold, to
obtain a sequence with comparatively good performance.
Specifically, after 2.sup.8.times.3.sup.2=2304 exhaustive searches
are performed, all possible S.sub.-2024:8:2024 and corresponding
PAPR values may be obtained, and S.sub.-2024:8:2024 with a smallest
PAPR is finally obtained through comparison. Table 6 shows a.sub.i
and c.sub.i in 10 groups of optimal S when the short training
sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s is designed based on the frequency-domain
sequence HES corresponding to the 80-MHz HE-STF with the
periodicity of 1.6 .mu.s.
Setting a preset threshold (for example, the preset fifth
threshold) may be performing exhaustion on the parameter set A and
the parameter set C, and performing setting based on a minimum PAPR
value (for example, 10 groups of results with minimum PAPRs in
Table 6) obtained in an exhaustion process, or may be performing
setting comprehensively with reference to a minimum PAPR value
obtained in an exhaustion result, a property of a sequence, and the
like, or may be performing setting comprehensively with reference
to a minimum PAPR value obtained in an exhaustion result, a preset
parameter, and the like; or the preset threshold may be specified
in advance; or the preset threshold may be obtained based on a
plurality of experiment results, or the like.
TABLE-US-00006 TABLE 6 Values of parameter sets for the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s Sequence number a.sub.1 a.sub.2 c.sub.1
c.sub.2 c.sub.3 c.sub.4 c.sub.5 c.sub.6 c.s- ub.7 c.sub.8 PAPR (dB)
1 -1 -1 1 -1 1 -1 1 1 -1 -1 6.1586 2 1 1 -1 1 -1 1 -1 -1 1 1 6.1586
3 0 -1 1 -1 1 -1 1 1 -1 -1 6.2975 4 0 1 -1 1 -1 1 -1 -1 1 1 6.2975
5 -1 0 1 -1 1 -1 1 1 -1 -1 6.2986 6 1 0 -1 1 -1 1 -1 -1 1 1 6.2986
7 1 -1 1 -1 1 -1 1 1 -1 -1 6.4188 8 -1 1 -1 1 -1 1 -1 -1 1 1 6.4188
9 0 0 1 -1 1 -1 1 1 -1 -1 6.4367 10 0 0 -1 1 -1 1 -1 -1 1 1
6.4367
The values of a.sub.i and c.sub.i in the obtained 10 groups of
results are separately substituted into the formula (7), and it can
be learned that the short training sequence S corresponding to the
320-MHz EHT-STF with the periodicity of 1.6 .mu.s may be expressed
as follows:
{L2, 0, -R2, -1, L2, 0, -R2, 0, L2, 0, R2, -1, -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 1, -L2, 0, R2, 0, -L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 0, L2, 0, -R2, 0, L2, 0, R2, -1, -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 0, -L2, 0, R2, 0, -L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, -1, L2, 0, -R2, 0, L2, 0, R2, 0, -L2, 0, -R2}(1+j)/
{square root over (2 )}; or
{-L2, 0, R2, 1, -L2, 0, R2, 0, -L2, 0, -R2, 0, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 1, L2, 0, -R2, 0, L2, 0, R2, -1, -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, -1, -L2, 0, R2, 0, -L2, 0, -R2, 1, L2, 0, R2}(1+j)/
{square root over (2)}; or
{L2, 0, -R2, 0, L2, 0, -R2, 0, L2, 0, R2, 0, -L2, 0, -R2}(1+j)/
{square root over (2)}; or
{-L2, 0, R2, 0, -L2, 0, R2, 0, -L2, 0, -R2, 0, L2, 0, R2}(1+j)/
{square root over (2)}.
L2 expressed as {M, -1, M, -1, -M, -1, M}, R2 expressed as {-M, 1,
M, 1, -M, 1, -M}, -L2={-M, 1, -M, 1, M, 1, -M}, and -R2 expressed
as {M, -1, -M, -1, M, -1, M} may be substituted to obtain the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s.
It should be noted that the short training sequence S corresponding
to the EHT-STF with the periodicity of 1.6 .mu.s and the channel
bandwidth of .sub.320 MHz may be expressed as any one of the
foregoing 10 expressions.
It can be learned from the foregoing that L2 and R2 are sequences
related to the short training sequence corresponding to 80 MHz and
the periodicity of 1.6 .mu.s. Therefore, the 320-MHz short training
sequence can be compatible with the 80-MHz short training sequence.
In addition, the 320-MHz short training sequence can support
automatic gain control on a high-bandwidth (the bandwidth is
greater than 160 MHz) channel. In addition, it is verified through
simulation and comparison between the PAPRs in Table 6 and the
PAPRs in 802.11ax (Table 1) that these short training sequences
have comparatively small peak-to-average power ratios, and
therefore can support automatic gain control on a high-bandwidth
channel and can improve an estimation effect for an automatic gain
control circuit at a receive end, thereby reducing a receive bit
error rate. Therefore, the short training sequence proposed for a
high channel bandwidth in this solution of this application can
control a PAPR to be very small.
Manner B
Obtain, based on a 160-MHz frequency-domain sequence HES with a
periodicity of 1.6 .mu.s, a short training sequence S corresponding
to a 320-MHz EHT-STF with a periodicity of 1.6 .mu.s.
The 320-MHz bandwidth has 2048.times.4=4096 tones in total. When
the periodicity included in the short training field is 1.6 .mu.s,
the short training sequence may be expressed as S.sub.-2040:8:2040,
where -2040 indicates a subscript of a starting tone, 2040
indicates a subscript of an ending tone, 8 indicates a spacing, and
-2040:8:2040 indicates starting with a tone whose subscript is 2040
and ending with a tone whose subscript is 2040, with a spacing of 8
tones in between. On other tones, a frequency-domain sequence value
is 0.
Similarly, in this embodiment of this application, the short
training sequence corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s may be determined by using at least the
following three methods.
Method 1
Determine, based on a frequency-domain sequence HES for a bandwidth
of a reference channel, the short training sequence S corresponding
to the 320-MHz EHT-STF with the periodicity of 1.6 .mu.s.
Optionally, the short training sequence corresponding to the
EHT-STF with the periodicity of 1.6 .mu.s and the target channel
bandwidth of 320 MHz may be expressed as follows:
{L4, 1, R4, 0, L4, -1, -R4}(1+j)/ {square root over (2)}; or
{-L4, -1, -R4, 0, L4, 1, R4}(1+j)/ {square root over (2)}; or
{L4, 0, R4, 0, L4, 0, -R4}(1+j)/ {square root over (2)}; or
{-L4, 0, -R4, 0, -L4, 0, R4}(1+j)/ {square root over (2)}; or
{L4, 0, R4, 0, L4, -1, -R4}(1+j)/ {square root over (2)}; or
{-L4, 0, -R4, 0, -L4, 1, R4}(1+j)/ {square root over (2)}; or
{L4, 0, -R4, 0, L4, 1, R4}(1+j)/ {square root over (2)}; or
{-L4, 0, R4, 0, -L4, -1, -R4}(1+j)/ {square root over (2)}; or
{L4, 1, R4, 0, L4, 0, -R4}(1+j)/ {square root over (2)}; or
{-L4, -1, -R4, 0, -L4, 0, R4}(1+j)/ {square root over (2)}, where
similarly,
L4=HES.sub.-1016:8:-8 {square root over (2)}/(1+j)={M, -1, M, -1,
-M, -1, M, 0, -M, 1, M, 1, -M, 1,-M}, and HES.sub.-1016:8:-8 is a
part of HES.sub.-1016:8:1016 on the left of a tone 0;
R4=HES.sub.8:8:1008 {square root over (2)}/(1+j)={-M, 1, -M, 1, M,
1, -M, 0, -M, 1, M, 1, -M, 1, -M}, and HES.sub.8:8:1008 is a part
of HES.sub.-1016:8:1016 on the right of the tone 0; and
HES.sub.-1008:16:1008 is an HES corresponding to 160 MHz and the
periodicity of 0.8 .mu.s.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -2040 and ends with a tone
whose subscript is 2040, with a spacing of 8 tones in between.
It should be noted that the short training sequence S corresponding
to the EHT-STF with the periodicity of 1.6 .mu.s and the channel
bandwidth of 320 MHz may be expressed as any one of the foregoing
10 expressions.
It can be learned from the foregoing that, by using the method 1,
the short training sequence S corresponding to the 320-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained through
transformation based on an HES specified in a standard.
Method 2
Obtain, through transformation based on an M-sequence, the short
training sequence S corresponding to the EHT-STF with the
periodicity of 1.6 .mu.s and the bandwidth of 320 MHz.
Specifically, L4 expressed as {M, -1, M, -1, -M, -1, M, 0, -M, 1,
M, 1, -M, 1, -M}, R4 expressed as {-M, 1, -M, 1, M, 1,-M, 0, -M, 1,
M, 1, -M, 1, -M}, -L4 expressed as {-M, 1, -M, 1, M, 1, -M, 0, M,
-1, -M, -1, M, -1, M}, and -R4 expressed as {M, -1, M, -1, -M, -1,
M, 0, M, -1, -M, -1, M, -1, M} are substituted, and it can be
learned that the 320-MHz EHT-STF with the periodicity of 1.6 .mu.s
may be expressed as follows:
{M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M,
1, M, -M, 0, -M, 1, M, 1, -M, 1, -M, 0, M, -1, M, -1, -M, -1, M, 0,
-M, 1, M, 1, -M, 1, -M, -1, M, -1, M, -1, -M, -1, M, 0, M, -1, -M,
-1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, -M, 1, -M, 1, M, 1,
-M, 0, M, -1, -M, -1, M, -1, M, 1, -M, 1, -M, 1, M, 1, -M, 0, -M,
1, M, 1, -M, 1, -M}(1+j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M, , -M, 1, -M,
1, M, i,-M, 0, -M, 1, M, 1, -M, 1, -M, 0, M, -1, M, -1, -M, -1, M,
0, -M, 1, M, 1, -M, 1, -M, 0, M, -1, M, -1, -M, -1, M, 0, M, -1,
-M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, -M, 1, -M, 1, M, 1,
-M, 0, M, -1, -M, -1, M, -1, M, 0, -M, 1, -M, 1, M, i,-M, 0, -M, 1,
M, 1, -M, 1, -M}(1+j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M,
1, M, i,-M, 0, -M, 1, M, 1, -M, 1, -M, 0, M, -1, M, -1, -M, -1, M,
0, -M, 1, M, 1, -M, 1, -M, -1, M, -1, M, -1, -M, -1, M, 0, M, -1,
-M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, -M, 1, -M, 1, M, 1,
-M, 0, M, -1, -M, -1, M, -1, M, 1, -M, 1, -M, 1, M, i,-M, 0, -M, 1,
M, 1, -M, 1, -M}(1+j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M, 0, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, M, -1, M, -1, -M, -1,
M, 0, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M, 1, M, i,-M, 0, -M, 1,
M, 1, -M, 1, -M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, 0, -M, 1, -M,
1, M, i,-M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M,
0, M, -1, -M, -1, M, -1, M, -1, M, -1, M, -1, -M, -1, M, 0, M, -1,
-M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M, 1, -M, 1, -M,
1, M, i,-M, 0, -M, 1, M, 1, -M, 1, -M, 0, M, -1, M, -1, -M, -1, M,
0, -M, 1, M, 1, -M, 1, -M, o, M, -1, M, -1, -M, -1, M, 0, M, -1,
-M, -1, M, -1, M}(1+j)/ {square root over (2)}; or
{-M, 1, -M, 1, M, 1, -M, 0, M, -1, -M, -1, M, -1, M, -1, M, -1, M,
-1, -M, -1, M, 0, M, -1, -M, -1, M, -1, M, 0, -M, 1, -M, 1, M, 1,
-M, 0, M, -1, -M, -1, M, -1, M, 0, -M, 1, -M, 1, M, 1,-M, 0, -M, 1,
M, 1, -M, 1, -M}(1+j)/ {square root over (2)}.
Therefore, the values given by the foregoing short training
sequence each correspond to a frequency-domain sequence value that
starts with a tone whose subscript is -2040 and ends with a tone
whose subscript is 2040, with a spacing of 8 tones in between.
It should be noted that the short training sequence S corresponding
to the EHT-STF with the periodicity of 1.6 .mu.s and the bandwidth
of 320 MHz may be expressed as any one of the foregoing 10
expressions.
It can be learned from the foregoing that, by using the method 2,
the short training sequence S corresponding to the 320-MHz EHT-STF
with the periodicity of 1.6 .mu.s may be obtained through
transformation based on the M-sequence.
Method 3
The short training sequence corresponding to the EHT-STF in the
foregoing method 1 or method 2 is directly cached or stored
locally. When the short training sequence corresponding to the
EHT-STF is to be used, the short training sequence corresponding to
the EHT-STF is directly obtained locally.
It should be understood that the foregoing three methods are merely
examples for description, and this application is not limited
thereto. Any method that can be used to obtain the short training
sequence corresponding to the 320-MHz EHT-STF with the periodicity
of 1.6 .mu.s falls within the protection scope of this embodiment
of this application.
Similar to that in the scenario 1, the short training sequence S
corresponding to the 320-MHz EHT-STF with the periodicity of 1.6
.mu.s may be obtained through simulation calculation. For example,
if the method 1 is used, the short training sequence S
corresponding to the 320-MHz EHT-STF with the periodicity of 1.6
.mu.s may be obtained through calculation based on a stored
frequency-domain sequence HES that corresponds to an HE-STF and by
using a corresponding formula. For another example, if the method 2
is used, the short training sequence S corresponding to the 320-MHz
EHT-STF with the periodicity of 1.6 .mu.s may be obtained through
calculation based on a stored or protocol-specified M-sequence by
using a corresponding formula.
Specifically, the 320-MHz EHT-STF may be alternatively constructed
by rotating and combining HE-STFs for channels with a bandwidth of
160 MHz. Specifically, the short training sequence S corresponding
to the 320-MHz EHT-STF with the periodicity of 1.6 .mu.s may be
generated based on the frequency-domain sequence
HES.sub.-1016:8:1016 defined in 802.11ax for the 160-MHz HE-STF
with the periodicity of 1.6 .mu.s. A detailed design formula
thereof is as follows: S.sub.-2040:8:2040={c.sub.1L4, a.sub.1,
c.sub.2R4, 0, c.sub.3L4, a.sub.2, c.sub.4R4}(1+j)/ {square root
over (2)} (8)
where
L4=HES.sub.-1016:8:-8 {square root over (2)}/(1+j)={-M, -1, M, -1,
-M, -1, -M, 0, -M, 1, M, 1, -M, 1, -M}:
R4=HES.sub.8:8:1008 {square root over (2)}/(1+j) ={-M, 1, -M, 1, M,
1, -M, 0, M, 1, M, 1, -M, 1, -M}; and
similarly,
a value of a.sub.i is {-1, 0, 1,} and i=1, 2; and
a value of c.sub.j is {-1, 1}, and j=1, 2, 3, 4.
Similarly, when the short training sequence S corresponding to the
320-MHz EHT-STF with the periodicity of 1.6 .mu.s is obtained by
using the method 1, the short training sequence S may be obtained
based on the stored HES.sub.-1016:8:-8 and HES.sub.8:8:1008 by
using the formula (8). Alternatively, when the short training
sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s is obtained by using the method 2, the
short training sequence S may be obtained based on the M-sequence
by using the formula (8).
The short training sequence S corresponding to the 320-MHz EHT-STF
with the periodicity of 1.6 .sub.las may be obtained based on the
formula (8). In addition, simulation calculation is performed, for
example, a.sub.i and c.sub.i are adjusted, so that a PAPR
corresponding to the short training sequence S corresponding to the
EHT-STF is less than or equal to a preset sixth threshold, to
obtain a sequence with comparatively good performance.
Specifically, after 2.sup.4.times.3.sup.2=144 exhaustive searches
are performed, all possible S.sub.-2040:8:2040 and corresponding
PAPR values may be obtained, and S.sub.-2040:8:2040 with a smallest
PAPR is finally obtained through comparison. Table 7 shows a.sub.i
and c.sub.i in 10 groups of optimal S when the short training
sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s is designed based on the short training
sequence corresponding to the 160-MHz HE-STF with the periodicity
of 1.6 .mu.s.
Setting a preset threshold (for example, the preset sixth
threshold) may be performing exhaustion on the parameter set A and
the parameter set C, and performing setting based on a minimum PAPR
value (for example, 10 groups of results with minimum PAPRs in
Table 7) obtained in an exhaustion process, or may be performing
setting comprehensively with reference to a minimum PAPR value
obtained in an exhaustion result, a property of a sequence, and the
like, or may be performing setting comprehensively with reference
to a minimum PAPR value obtained in an exhaustion result, a preset
parameter, and the like; or the preset threshold may be specified
in advance; or the preset threshold may be obtained based on a
plurality of experiment results, or the like.
TABLE-US-00007 TABLE 7 Values of parameter sets for the short
training sequence S corresponding to the 320-MHz EHT-STF with the
periodicity of 1.6 .mu.s Sequence PAPR number a.sub.1 a.sub.2
c.sub.1 c.sub.2 c.sub.3 c.sub.4 (dB) 1 1 -1 1 1 1 -1 6.5894 2 -1 1
-1 -1 -1 1 6.5894 3 0 0 1 1 1 -1 6.599 4 0 0 -1 -1 -1 1 6.599 5 0
-1 1 1 1 -1 6.6319 6 0 1 -1 -1 -1 1 6.6319 7 0 1 1 -1 1 1 6.6514 8
0 -1 -1 1 -1 -1 6.6514 9 1 0 1 1 1 -1 6.6685 10 -1 0 -1 -1 -1 1
6.6685
The values of a.sub.i, and c.sub.i, in the obtained 10 groups of
results are separately substituted into the formula (8), and it can
be learned that the short training sequence S corresponding to the
320-MHz EHT-STF with the periodicity of 1.6 .mu.s may be expressed
as follows:
{L4, 1, R4, 0, L4, -1, -R4}(1+j)/ {square root over (2)}; or
{-L4, -1, -R4, 0, -L4, 1, R4}(1+j)/ {square root over (2)}; or
{L4, 0, R4, 0, L4, 0, -R4}(1+j)/ {square root over (2)}; or
{-L4, 0, -R4, 0, -L4, 0, R4}(1+j)/ {square root over (2)}; or
{L4, 0, R4, 0, L4, -1, -R4}(1+j)/ {square root over (2)}; or
{-L4, 0, -R4, 0, -L4, 1, R4}(1+j)/ {square root over (2)}; or
{L4, 0, -R4, 0, L4, 1, R4}(1+j)/ {square root over (2)}; or
{-L4, 0, R4, 0, -L4, -1, -R4}(1+j)/ {square root over (2)}; or
{L4, 1, R4, 0, L4, 0, -R4}(1+j)/ {square root over (2)}; or
{-L4, -1, -R4, 0, -L4, 0, R4}(1+J)/ {square root over (2)}.
L4 expressed as {M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1,
-M},R4 expressed as {-M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1 -M, 1,
-M}, -L4 expressed as {-M, 1, -M, 1, M, 1, -M, 0, M, -1, -M, -1, M,
-1, M}, and -R4 expressed as {M, -1, M, -1, -M, -1, M, 0, M, -1,
-M, -1, M, -1, M} may be substituted to obtain the short training
sequence corresponding to the 320-MHz EHT-STF with the periodicity
of 1.6 .mu.s.
It should be noted that the short training sequence S corresponding
to the EHT-STF with the periodicity of 1.6 .mu.s and the channel
bandwidth of 320 MHz may be expressed as any one of the foregoing
10 expressions.
It should be noted that the foregoing manner A and manner B are
merely examples for description, and this application is not
limited thereto.
It can be learned from the foregoing that L4 and R4 are sequences
related to the short training sequence corresponding to 160 MHz and
the periodicity of 1.6 .mu.s. Therefore, the 320-MHz short training
sequence can be compatible with the 160-MHz short training
sequence. In addition, the 320-MHz short training sequence can
support automatic gain control on a high-bandwidth (the bandwidth
is greater than 160 MHz) channel. In addition, it is verified
through simulation and comparison between the PAPRs in Table 7 and
the PAPRs in 802.11ax (Table 1) that these short training sequences
have comparatively small peak-to-average power ratios, and
therefore can support automatic gain control on a high-bandwidth
channel and can improve an estimation effect for an automatic gain
control circuit at a receive end, thereby reducing a receive bit
error rate. Therefore, the short training sequence proposed for a
high channel bandwidth in this solution of this application can
control a PAPR to be very small.
It can be learned from the foregoing that, in this embodiment of
this application, the short training sequence corresponding to the
240-MHz EHT-STF and the short training sequence corresponding to
the 320-MHz EHT-STF are proposed, and the short training sequence
corresponding to the EHT-STF may be directly stored at a local end;
or the M-sequence may be stored at a local end or specified in a
protocol, and the short training sequence corresponding to the
EHT-STF is obtained through calculation based on the M-sequence by
using a corresponding formula; or the short training sequence
corresponding to the HE-STF may be stored, and the short training
sequence corresponding to the EHT-STF may be obtained through
calculation based on the short training sequence corresponding to
the HE-STF by using a corresponding formula. This is not limited in
this embodiment of this application.
It should be noted that the foregoing describes in detail the
method provided in this application by using only 240 MHz and 320
MHz as examples, but this should not constitute a limitation on a
channel bandwidth to which the method provided in this application
is applicable. Short training sequences corresponding to other
bandwidths greater than 160 MHz, for example, 200 MHz and 280 MHz,
may also be obtained according to the short training sequence
design method provided in this embodiment of this application, and
can be all compatible with an existing 80-MHz short training
sequence (or a rotation factor). Based on the short training
sequence design method provided in this application, a person
skilled in the art may easily figure out that the method may be
applied to a channel bandwidth of another size after undergoing a
change or a substitution.
It can be learned from the foregoing that, for 240 MHz or 320 MHz
and the periodicity of 0.8 .mu.s or 1.6 .mu.s, 10 short training
sequences S corresponding to an EHT-STF are proposed based on the
frequency-domain sequence HES corresponding to the HE-STF with the
bandwidth of 80 MHz and the frequency-domain sequence HES
corresponding to the HE-STF with the bandwidth of 160 MHz.
Therefore, compatibility with the existing HE-STF with the
bandwidth of 80 MHz in 802.11ax is considered for both the EHT-STF
for the channel with the bandwidth of 240 MHz and the EHT-STF for
the channel with the bandwidth of 320 MHz, and compatibility with
the existing 160-MHz HE-STF in 802.11ax is further considered for
the EHT-STF for the channel with the bandwidth of 320 MHz. In
addition, in this embodiment of this application, for the channel
with the bandwidth of 240 MHz and the channel with the bandwidth of
320 MHz, exhaustive simulation is performed on parameters, and the
PAPRs in Table 2 to Table 7 are compared with the PAPRs in 802.11ax
(Table 1), to verify that the short training sequence provided in
this embodiment of this application corresponds to a comparatively
small peak-to-average power ratio PAPR and has comparatively good
performance, thereby improving an estimation effect for an
automatic gain control circuit at a receive end, and reducing a
receive bit error rate. Therefore, the short training sequence
proposed for a high channel bandwidth in this solution of this
application can control a PAPR to be very small.
The foregoing describes in detail the short training field sending
method provided in the embodiments of this application with
reference to FIG. 1 to FIG. 6. The following describes in detail a
short training field sending apparatus provided in the embodiments
of this application with reference to FIG. 7 and FIG. 8.
FIG. 7 is a schematic block diagram of a short training field
sending apparatus according to an embodiment of this application.
As shown in FIG. 7, the apparatus 700 may include a determining
module 710 and a sending module 720.
In a possible design, the apparatus 700 may correspond to the
network device in the foregoing method embodiment, for example, may
be the network device, or a chip configured in the network
device.
The determining module 710 is configured to determine a short
training sequence.
The sending module 720 is configured to send a short training field
on a target channel. The short training field is obtained by
performing inverse fast Fourier transformation IFFT on the short
training sequence. A bandwidth of the target channel is greater
than 160 MHz.
Specifically, the apparatus 700 may include modules configured to
perform the method performed by the network device in the method
200. In addition, the modules in the apparatus 700 and the
foregoing other operations and/or functions are separately used to
implement corresponding procedures of the method 200 in FIG. 5.
When the apparatus 700 is configured to perform the method 200 in
FIG. 5, the determining module 710 may be configured to perform
step 210 in the method 200 and a step of generating a short
training sequence, and the sending module 720 may be configured to
perform step 220 in the method 200.
It should be understood that specific processes of performing the
foregoing corresponding steps by the modules are described in
detail in the foregoing method embodiment. For brevity, details are
not described herein again.
It should be further understood that the determining module 710 in
the apparatus 700 may correspond to a processor 810 in a network
device 800 shown in FIG. 8, and the sending module 720 may
correspond to a transceiver 820 in the network device 800 shown in
FIG. 8.
FIG. 8 is a schematic structural diagram of the network device 800
according to an embodiment of this application. As shown in FIG. 8,
the network device 800 includes the processor 810 and the
transceiver 820. Optionally, the network device 800 further
includes a memory 830. The processor 810, the transceiver 820, and
the memory 830 communicate with each other through an internal
connection path, and transfer a control signal and/or a data
signal. The memory 830 is configured to store a computer program,
and the processor 810 is configured to invoke the computer program
from the memory 830 and run the computer program, to control the
transceiver 820 to transmit or receive a signal.
The processor 810 and the memory 830 may be combined into one
processing apparatus, and the processor 810 is configured to
execute program code stored in the memory 830 to implement the
foregoing functions. During specific implementation, the memory 830
may be alternatively integrated in the processor 810, or may be
independent of the processor 810.
The network device 800 may further include an antenna 840,
configured to send, by using a radio signal, a short training field
output by the transceiver 820.
When a program instruction stored in the memory 830 is executed by
the processor 810, the processor 810 is configured to determine a
short training sequence.
Specifically, the network device 800 may include modules configured
to perform the method 200 in FIG. 5. In addition, the modules in
the network device 800 and the foregoing other operations and/or
functions are separately used to implement corresponding procedures
of the method 200 in FIG. 5. Specific processes of performing the
foregoing corresponding steps by the modules are described in
detail in the foregoing method embodiment. For brevity, details are
not described herein again.
The processor 810 may be configured to perform an internal
implementation action described in the foregoing method embodiment.
For details, refer to the descriptions in the foregoing method
embodiment. Details are not described herein again.
It should be understood that the processor in this embodiment of
this application may be a central processing unit (CPU), or the
processor may be another general-purpose processor, a digital
signal processor (DSP), an application-specific integrated circuit
(ASIC), a field programmable gate array (FPGA) or another
programmable logic device, a discrete gate or transistor logic
device, a discrete hardware component, or the like.
It should be further understood that the memory in this embodiment
of this application may be a volatile memory or a non-volatile
memory, or may include both a volatile memory and a non-volatile
memory. The non-volatile memory may be a read-only memory (ROM), a
programmable read-only memory (PROM), an erasable programmable
read-only memory (EPROM), an electrically erasable programmable
read-only memory (EEPROM), or a flash memory. The volatile memory
may be a random access memory (RAM), which serves as an external
cache. Through example but not limitative description, many forms
of random access memories (RAM) may be used, for example, a static
random access memory (static RAM, SRAM), a dynamic random access
memory (DRAM), a synchronous dynamic random access memory
(synchronous DRAM, SDRAM), a double data rate synchronous dynamic
random access memory (double data rate SDRAM, DDR SDRAM), an
enhanced synchronous dynamic random access memory (enhanced SDRAM,
ESDRAM), a synchronous link dynamic random access memory (synchlink
DRAM, SLDRAM), and a direct rambus random access memory (direct
rambus RAM, DR RAM).
According to the method provided in the embodiments of this
application, this application further provides a computer program
product. The computer program product includes computer program
code. When the computer program code runs on a computer, the
computer is enabled to perform the method in the embodiment shown
in FIG. 5.
According to the method provided in the embodiments of this
application, this application further provides a computer-readable
medium. The computer-readable medium stores program code. When the
program code runs on a computer, the computer is enabled to perform
the method in the embodiment shown in FIG. 5.
According to the method provided in the embodiments of this
application, this application further provides a system, including
the foregoing one or more terminal devices and one or more network
devices.
A person of ordinary skill in the art may be aware that, in
combination with the examples described in the embodiments
disclosed in this specification, units, algorithms, and steps may
be implemented by electronic hardware or a combination of computer
software and electronic hardware. Whether these functions are
performed by hardware or software depends on particular
applications and design constraints of the technical solutions. A
person skilled in the art may use different methods to implement
the described functions for each particular application, but it
should not be considered that the implementation goes beyond the
scope of this application.
It can be clearly understood by a person skilled in the art that,
for convenience and brevity of description, for a detailed working
process of the foregoing system, apparatus, and unit, reference may
be made to a corresponding process in the foregoing method
embodiment, and details are not described herein again.
In the several embodiments provided in this application, it should
be understood that the disclosed system, apparatus, and method may
be implemented in other manners. For example, the described
apparatus embodiment is merely an example. For example, the unit
division is merely logical function division and may be other
division in actual implementation. For example, a plurality of
units or components may be combined or integrated into another
system, or some features may be ignored or not performed. In
addition, the displayed or discussed mutual couplings or direct
couplings or communication connections may be implemented by using
some interfaces. The indirect couplings or communication
connections between the apparatuses or units may be implemented in
electrical, mechanical, or other forms.
The units described as separate parts may or may not be physically
separate, and parts displayed as units may or may not be physical
units, may be located in one position, or may be distributed on a
plurality of network units. Some or all of the units may be
selected based on actual requirements to achieve the objectives of
the solutions of the embodiments.
In addition, functional units in the embodiments of this
application may be integrated into one processing unit, or each of
the units may exist alone physically, or two or more units may be
integrated into one unit.
When the function is implemented in a form of a software functional
unit and sold or used as an independent product, the function may
be stored in a computer-readable storage medium. Based on such an
understanding, the technical solutions of this application
essentially, or the part contributing to the prior art, or some of
the technical solutions may be implemented in a form of a software
product. The computer software product is stored in a storage
medium and includes several instructions for instructing a computer
device (which may be a personal computer, a server, a network
device, or the like) to perform all or some of the steps of the
methods described in the embodiments of this application. The
storage medium includes any medium that can store program code, for
example, a USB flash drive, a removable hard disk, a read-only
memory (ROM), a random access memory (RAM), a magnetic disk, or an
optical disc.
The foregoing descriptions are merely specific implementations of
this application, but are not intended to limit the protection
scope of this application. Any variation or replacement readily
figured out by a person skilled in the art within the technical
scope disclosed in this application shall fall within the
protection scope of this application. Therefore, the protection
scope of this application shall be subject to the protection scope
of the claims.
* * * * *